Add dma memcpy api to the default spi_flash_copy_mmap(), so that
dma will be used to copy data when CONFIG_DMA is defined for the
platform.
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>