dmaengine: tegra-apb: Remove duplicated pending_sg_req checks

There are few place in the code which check whether pending_sg_req list is
empty despite of the check already being done. Let's remove the duplicated
checks to keep code clean.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20200209163356.6439-12-digetx@gmail.com


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