Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFp4: Integrate a boatload of bug fixes from p4. We're right on the
8k boundary with this program still.

text data bss dec hex filename
7925 4 4476 12405 3075 bootiic.out

so we have like 293 bytes left before we have to play games. There
may be ways to reduce that somewhat, but they start to be very board
specific.

MFp4:
Init eeprom here now that we don't init the eeprom in arm_init.s
and read in the second 8k of the data.
Tweak formatting.

MFp4 (checkpoint of work in progress):

o Use a directory layout that is more akin to the i386 boot layout.
o Create a libat91 for library routines that are used by one or more
of the boot loaders.
o Create bootiic for booting from an iic part.
o Create bootspi for booting from an spi part.
o Optimize the size of many of these routines (especially emac.c). Except
for the emac.c optimizations, all these have been tested.
o eliminate the inc directory, libat91 superceeds it.
o Move linker.cfg up a layer to allow it to be shared.