mmc: MMC_GOLDFISH should depend on HAS_DMA

If NO_DMA=y:

    ERROR: dma_unmap_sg [drivers/mmc/host/android-goldfish.ko] undefined!
    ERROR: dma_alloc_coherent [drivers/mmc/host/android-goldfish.ko] undefined!
    ERROR: dma_map_sg [drivers/mmc/host/android-goldfish.ko] undefined!
    ERROR: dma_free_coherent [drivers/mmc/host/android-goldfish.ko] undefined!

Add a dependency on HAS_DMA to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>