V4L/DVB: videobuf: add missing checks for kzalloc returning NULL

Signed-off-by: NPawel Osciak <p.osciak@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf-dma-sg.c

@@ -418,6 +418,8 @@ static void *__videobuf_alloc(size_t size)
 	struct videobuf_buffer *vb;
 
 	vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
+	if (!vb)
+		return vb;
 
 	mem = vb->priv = ((char *)vb)+size;
 	mem->magic=MAGIC_SG_MEM;

drivers/media/video/videobuf-vmalloc.c

@@ -138,6 +138,8 @@ static void *__videobuf_alloc(size_t size)
 	struct videobuf_buffer *vb;
 
 	vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
+	if (!vb)
+		return vb;
 
 	mem = vb->priv = ((char *)vb)+size;
 	mem->magic=MAGIC_VMAL_MEM;