V4L/DVB (13343): v4l: add more missing linux/sched.h includes

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/videobuf-dma-contig.c b/drivers/media/video/videobuf-dma-contig.c
index 635ffc7..c3065c4 100644
--- a/drivers/media/video/videobuf-dma-contig.c
+++ b/drivers/media/video/videobuf-dma-contig.c
@@ -19,6 +19,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/dma-mapping.h>
+#include <linux/sched.h>
 #include <media/videobuf-dma-contig.h>
 
 struct videobuf_dma_contig_memory {