dmaengine: ti: k3-udma: Remove redundant is_slave_direction() checks

The direction has been already validated in the main callback and there is
no need to check it again in the TR mode handlers for slave_sg and cyclic.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20200824120120.9270-1-peter.ujfalusi@ti.com


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