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

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

Use the pin number rather than the hybrid pin number + name.

Load the bytes into the EMAC's MAC address register in the proper
order. The kernel used to shuffle them around to get things right,
but that was recently fixed. This makes our boot loader match the
behavior of most other boot loaders for the atmel parts. This bug was
inherited from the Kwikbyte loader that we started from.

This bug was discovered by Bj?\027.A?\027Nvrn K?\027Nvnig back in June, but fell on the
floor. He provided patches to the kernel, include backwards
compatibility options that were similar to Olivier's if_ate.c commit.

MFp4: differences for bwct ethernet attachment

MFp4: boot on KB9202 correctly. Also, reduce the size of the SD/MMC driver
somewhat.

MFp4:

Massive update. The highlights:
o dramatically cut memory usage by writing better, less intertwingled
code.
o implement booting off mmc/sd cards (sd only tested one at the moment)
o start to split out board specific stuff for boot2.

MFp4: First cut at making spi and/or sd card booting work, needs work