dmaengine: pl330: Remove unreachable code

_setup_req(..) never returns negative value.
Hence the condition ret < 0 is never met

Signed-off-by: Surendran K <surendran.k@samsung.com>
Link: https://lore.kernel.org/r/20201016103347.63084-1-surendran.k@samsung.com


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