Since r273264 the SD card detection on Raspberry Pi is reliably working and
that expose new bugs with HS mode.

When the old code could not do the proper card detection it would boot with
lower defaults (and no HS mode) and this makes some HS cards boots.

Now, with the card always identified as HS capable, the sdhci controller
tries to run the card at HS speeds and makes the boot always fail.

Disable the HS mode for now (which still can be enabled with the tunable)
until it is properly fixed.

MFC with:	r273264
Requested by:	many
SEEK_DATA has interesting behaviour for sparse files on ZFS.  A sparse file
with 128K of random data and truncated to 800K can have SEEK_DATA return -1
when given an offset of 128K. On UFS, the SEEK_DATA returns 800K (the size
of the file). SEEK_HOLE on ZFS seems to behave the same as UFS.

To handle this, map -1 to the size of the file (`end') when lseek returns
this for either SEEK_HOLE or SEEK_DATA. When sparse files are not supported
by the file system both `hole' and `data' will now be equal to `end' and we
will treat the entire file as data. This way, the -1 return for SEEK_DATA
on ZFS will end up doing the right thing.

Reported by: gjb@

MFC after:	3 days
Improve CAM's reaction on asymmetric access errors.

MFC after:	1 month
Bugfixes for the imx5/imx6 iomux fdt_pinctrl driver.

I originally overlooked a couple flag bits defined in the fdt binding docs.
One flag suppresses the pad configuration (pullup/pulldown/etc).  The other
one requires that the SION (set input on) flag be set in the mux register.

Also, it appears from the data involved that if the input register
address in the config tuple is zero, there is no input configuration.  The
old code was writing to register zero, which contains a collection of misc
control bits (having nothing to do with input configuration) that probably
shouldn't get overwritten arbitrarily.  The bindings doc doesn't explictly
mention this.
Remove an #ifdef DEBUG wrapper, and instead use if (bootverbose).
Fix the reversed sense of the PADCONF_NONE test.
Fix the error checking, broken on r273337, to _not_ ignore controller
errors.

Without this fix you can't even scan the bus (all operations will always
succeed).

MFC with:	r273337
Pointy hat to:	loos
Fix a few cases of use of uninitialized variables.  Found with -Wall.

MFC after:	1 week