ARM: mxs: Add STKa28 board from TQ-Group

The board uses an i.MX28 SoC, has an integrated eMMC.

Signed-off-by: Andreas Wass <andreas.wass@dalelven.com>
Fixed SSP1 pin configurations
Added board config file and added the board to boards.cfg
Removed NAND ENV defines. Removed VIDEO config.

Fixed comment header
Fixed some FEC stuff, and WP for MMC