Flip the boards to use the generic bounce buffer instead of the
MMC one.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andy Fleming <afleming@freescale.com>
Cc: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>