MLK-21400 mx6solosabre: Enable fastboot for UUU support

Enable fastboot configurations in mx6solo sabresd and sabreauto
defconfigs to support UUU. Since the DDR size on mx6solo sabre
boards is smaller, also change the fastboot buffer to 256MB.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
7 files changed