Create a few generic functions and drivers for powerpc.
First, we have a generic pci_machdep.c, which is incomplete, but contains
a number of functions that are generally present in all powerpc
pci_machdep.c implementations.
Second, we have a generic implementation of indirect configuration space
read/write.
Lastly, a generic pchb driver for most of the ppc ports.
Add the generic pci_machdep.h header file, which allows a port to use the
generic pci functions.
Convert prep to use the new generic powerpc PCI stuff.  There are
probably a few more things that can be made generic here.  Tested on
7248-100.
Per suggestion from Matt, rename these two files.
Track rename of generic pci files
Add a generic pci_intr_map() function (looks like macppc and ibmnws use this)
change prep_pct to genppc_pct to share better
Change some isa things around in the prep port to promote sharing of isa
Rename the prep isa io and mem bus space tags to genppc_* to promote
sharing of isa functionality.
first try on a generic interrupt handler.
Features:
- PIC details are hidden by struct pic_ops
- PICs can easily be cascaded
- support for soft interrupts
tested so far only on macppc with a PowerBook 3400c
order priorities like everyone else - low number, low priority - high
number, high priority
also add prototypes for PIC probe/setup functions
use generic interrupt handling, so far only ohare-based machines are supported
add options pfr various interrupt controllers, enable only PIC_OHARE
Commonize some more of this code to prepare for sharing
Copy prep's pcib.c over to here as a shared version.
prep now uses the shared copies of isadma_machdep.c and pcib.c
make this compile without PREP_BUS_SPACE_IO
Move prep's isapnp_machdep.c to powerpc/isa, and make prep use that instead.
use generic pchb.c from arch/powerpc
add heathrow PIC support
enable Heathrow PIC support