u-boot: add patch from gumstix u-boot repo

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
u-boot: add patch for Alto35 support

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
u-boot: add patch for more Gumstix expansion boards.

This adds eeprom ids for Stagecoach, Thumbo and Turtlecore.