dmaengine: cleanup with list_first_entry_or_null()

The combo of list_empty() check and return list_first_entry()
can be replaced with list_first_entry_or_null().

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index e4acd63..a373eca 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -1553,15 +1553,8 @@
 static struct coh901318_desc *
 coh901318_first_active_get(struct coh901318_chan *cohc)
 {
-	struct coh901318_desc *d;
-
-	if (list_empty(&cohc->active))
-		return NULL;
-
-	d = list_first_entry(&cohc->active,
-			     struct coh901318_desc,
-			     node);
-	return d;
+	return list_first_entry_or_null(&cohc->active, struct coh901318_desc,
+					node);
 }
 
 static void
@@ -1579,15 +1572,8 @@
 static struct coh901318_desc *
 coh901318_first_queued(struct coh901318_chan *cohc)
 {
-	struct coh901318_desc *d;
-
-	if (list_empty(&cohc->queue))
-		return NULL;
-
-	d = list_first_entry(&cohc->queue,
-			     struct coh901318_desc,
-			     node);
-	return d;
+	return list_first_entry_or_null(&cohc->queue, struct coh901318_desc,
+					node);
 }
 
 static inline u32 coh901318_get_bytes_in_lli(struct coh901318_lli *in_lli)