DMAengine uses the DMA engine device structure when mapping/unmapping
memory for DMA, so the MMC devices do not need their DMA masks
initialized (this reflects hardware: the MMC device is not the device
doing DMA.)
Tested-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>