Clang warns when one enumerated type is converted implicitly to another.

drivers/mtd/spi-nor/cadence-quadspi.c:962:47: warning: implicit
conversion from enumeration type 'enum dma_transfer_direction' to
different enumeration type 'enum dma_data_direction' [-Wenum-conversion]
        dma_dst = dma_map_single(nor->dev, buf, len, DMA_DEV_TO_MEM);
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
./include/linux/dma-mapping.h:428:66: note: expanded from macro
'dma_map_single'
                                   ~~~~~~~~~~~~~~~~~~~~          ^
drivers/mtd/spi-nor/cadence-quadspi.c:997:43: warning: implicit
conversion from enumeration type 'enum dma_transfer_direction' to
different enumeration type 'enum dma_data_direction' [-Wenum-conversion]
        dma_unmap_single(nor->dev, dma_dst, len, DMA_DEV_TO_MEM);
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
./include/linux/dma-mapping.h:429:70: note: expanded from macro
'dma_unmap_single'
                                     ~~~~~~~~~~~~~~~~~~~~~~          ^
2 warnings generated.

Use the proper enums from dma_data_direction to satisfy Clang.

DMA_FROM_DEVICE = DMA_DEV_TO_MEM = 2

Link: https://github.com/ClangBuiltLinux/linux/issues/108Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>