Handle active IMCs in AMD chipsets.

Detect and temporarily disable the IMC while accessing the flash.
Disable writes on default, but allow the user to enforce it.

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Stefan Tauner <stefan.tauner@student.tuwien.ac.at>
Add a bunch of new/tested stuff and various small changes 18.

Tested mainboards:
OK:
 - ASUS C60M1-I
   http://www.flashrom.org/pipermail/flashrom/2013-February/010578.html
 - ASUS P8H77-M
   http://www.flashrom.org/pipermail/flashrom/2013-May/010994.html
 - ASUS P8P67 LE (B2)
   http://www.flashrom.org/pipermail/flashrom/2013-May/010972.html
 - MSI B75MA-E33 (MS-7808)
   http://www.flashrom.org/pipermail/flashrom/2013-March/010659.html
 - MSI H77MA-G43 (MS-7756)
   http://www.flashrom.org/pipermail/flashrom/2013-April/010853.html
 - MSI KA780G (MS-7551)
   http://paste.flashrom.org/view.php?id=1617
 - ASUS P8H77-I
   http://www.flashrom.org/pipermail/flashrom/2013-March/010607.html
NOT OK:
 - ASRock Fatal1ty Z77 Performance
   http://www.flashrom.org/pipermail/flashrom/2013-January/010467.html
 - ASRock Z68 Extreme4
   http://www.flashrom.org/pipermail/flashrom/2013-May/010984.html
 - ASUS P8B75-M LE
   http://www.flashrom.org/pipermail/flashrom/2013-April/010867.html
 - ASUS P8P67-M PRO
   http://www.flashrom.org/pipermail/flashrom/2013-February/010541.html
 - ASUS P8Z68-V LE
   http://www.flashrom.org/pipermail/flashrom/2013-February/010582.html
 - Intel DQ77MK
   http://paste.flashrom.org/view.php?id=1603
 - Supermicro X9DRD-7LN4F
   http://paste.flashrom.org/view.php?id=1582
 - Supermicro X9SCE-F
   http://www.flashrom.org/pipermail/flashrom/2013-February/010588.html
 - Supermicro X9SCM-F
   http://www.flashrom.org/pipermail/flashrom/2013-February/010527.html
 - Tyan S7066
   http://www.flashrom.org/pipermail/flashrom/2013-March/010630.html

Chipsets:
 - Marked Intel B75 as tested
   http://www.flashrom.org/pipermail/flashrom/2013-March/010659.html
 - Marked Intel H77 as tested
   http://www.flashrom.org/pipermail/flashrom/2013-March/010607.html
 - Removed 10de:03e2 because it is apparently the MCP61 host bridge.
   It was reclassified to Host Bridge in the PCI device ID database and there
   is at least one report suggesting this configuration too:
   http://www.flashrom.org/pipermail/flashrom/2012-August/009716.html
 - Added MCP89 which hopefully works with the code for previous versions.
   Thanks to James Laird for submitting this change.

Tested flash chips:
 - Atmel AT25DF641(A) to PREW (+PREW)
   http://www.flashrom.org/pipermail/flashrom/2013-June/011113.html
 - Atmel AT25F512 to PREW (+PREW)
   http://www.flashrom.org/pipermail/flashrom/2013-April/010904.html
   Also, change its ID according to Modification of PCN SC040401A:
   "There has been a change in the returned value of the Product Identification
   (RDID) command, the AT25F512A RDID code is 65h compared to 60h from
   the AT25F512 product."
   It seems to be quite likely that all AT25F512 are fully functional relabeled
   AT25F1024 chips. There are even some hints in the datasheet:
   in table 6 they stress that address pin 16 needs to be low under all circum-
   stances; while continuous reads can wrap around on the AT25F1024 the DS
   notes "For the AT25F512, the read command must be terminated when the
   highest address (00FFFF) is reached." OTOH the lock bit semantics are
   different, but this has not been tested thoroughly
 - Atmel AT25F512A to PREW (+PREW)
   http://paste.flashrom.org/view.php?id=1569
 - Eon EN25F05 to PREW (+PREW)
   http://paste.flashrom.org/view.php?id=1571
 - Macronix MX25L12805(D) to PREW (+REW)
   http://www.flashrom.org/pipermail/flashrom/2013-April/010913.html
 - SST SST25VF040B to PREW (+PREW)
   http://paste.flashrom.org/view.php?id=1574
 - SST SST25VF040B.REMS to PREW (+EW)
   http://paste.flashrom.org/view.php?id=1575
 - ST M25P05-A to PREW (+PREW)
   http://paste.flashrom.org/view.php?id=1576
 - ST M29W512B to PREW (+W)
   http://www.flashrom.org/pipermail/flashrom/2013-March/010635.html
 - Winbond W25Q128.V to PREW (+REW)
   http://www.flashrom.org/pipermail/flashrom/2013-June/011108.html
 - Winbond W25X20 to PREW (+PREW)
   http://www.flashrom.org/pipermail/flashrom/2013-May/010990.html

Miscellaneous:
 - Add Lenovo X201 to the laptop whitelist.
 - Add chip IDs for the ESMT F25L..QA family.
 - The list of flashchips is not sorted strictly alphabetically and should not be
   either. Refine the comment explaining the scheme on top of the list.
 - Tiny other stuff.

Signed-off-by: Stefan Tauner <stefan.tauner@student.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@student.tuwien.ac.at>