V4L/DVB (4261): Included required header for in-kernel compilation

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/pvrusb2/pvrusb2-v4l2.c b/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
index 37dc5d7..9619510 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
@@ -21,6 +21,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/version.h>
 #include "pvrusb2-context.h"
 #include "pvrusb2-hdw.h"
 #include "pvrusb2.h"