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

drivers/dma/tegra20-apb-dma.c

@@ -504,9 +504,6 @@ static void tdc_start_head_req(struct tegra_dma_channel *tdc)
 {
 	struct tegra_dma_sg_req *sg_req;
 
-	if (list_empty(&tdc->pending_sg_req))
-		return;
-
 	sg_req = list_first_entry(&tdc->pending_sg_req, typeof(*sg_req), node);
 	tegra_dma_start(tdc, sg_req);
 	sg_req->configured = true;
@@ -518,9 +515,6 @@ static void tdc_configure_next_head_desc(struct tegra_dma_channel *tdc)
 {
 	struct tegra_dma_sg_req *hsgreq, *hnsgreq;
 
-	if (list_empty(&tdc->pending_sg_req))
-		return;
-
 	hsgreq = list_first_entry(&tdc->pending_sg_req, typeof(*hsgreq), node);
 	if (!list_is_last(&hsgreq->node, &tdc->pending_sg_req)) {
 		hnsgreq = list_first_entry(&hsgreq->node, typeof(*hnsgreq),
@@ -567,12 +561,6 @@ static bool handle_continuous_head_request(struct tegra_dma_channel *tdc,
 {
 	struct tegra_dma_sg_req *hsgreq;
 
-	if (list_empty(&tdc->pending_sg_req)) {
-		dev_err(tdc2dev(tdc), "DMA is running without req\n");
-		tegra_dma_stop(tdc);
-		return false;
-	}
-
 	/*
 	 * Check that head req on list should be in flight.
 	 * If it is not in flight then abort transfer as