imx6: wandboard: allow booting from MMC 2

One of the SD-CARD slots on the Wandboard Quad B1 is MMC 2. Enable it as a
boot device.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
1 file changed