V4L/DVB (7732): vivi: fix a warning

some gcc versions complain that fh is used without being defined.

The error report is bogus. However, fixing it is trivial. Better to make
gcc happy.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c
index b1e9592..845be18 100644
--- a/drivers/media/video/vivi.c
+++ b/drivers/media/video/vivi.c
@@ -888,7 +888,7 @@
 {
 	int minor = iminor(inode);
 	struct vivi_dev *dev;
-	struct vivi_fh *fh;
+	struct vivi_fh *fh = NULL;
 	int i;
 	int retval = 0;