M28: Pull out CONFIG_APBH_DMA so it's always enabled

The ABPH DMA is now used also by the SD card. Therefore it has to be enabled
even if NAND is disabled.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>