dmaengine: fix is_slave_direction() return false when DMA_DEV_TO_DEV

is_slave_direction() should return true when direction is DMA_DEV_TO_DEV.

Fixes: 49920bc6

 ("dmaengine: add new enum dma_transfer_direction")
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240123172842.3764529-1-Frank.Li@nxp.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>