mtd: MTD_NAND_DENALI should depend on HAS_DMA

If NO_DMA=y:

drivers/built-in.o: In function `denali_remove':
drivers/mtd/nand/denali.c:1605: undefined reference to `dma_unmap_single'
drivers/built-in.o: In function `denali_read_page_raw':
drivers/mtd/nand/denali.c:1190: undefined reference to `dma_sync_single_for_cpu'
drivers/built-in.o: In function `denali_read_page':
drivers/mtd/nand/denali.c:1140: undefined reference to `dma_sync_single_for_cpu'
drivers/built-in.o: In function `write_page':
drivers/mtd/nand/denali.c:1051: undefined reference to `dma_sync_single_for_cpu'
drivers/built-in.o: In function `denali_init':
drivers/mtd/nand/denali.c:1433: undefined reference to `dma_set_mask'
drivers/mtd/nand/denali.c:1438: undefined reference to `dma_map_single'
drivers/mtd/nand/denali.c:1442: undefined reference to `dma_mapping_error'

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>