media: ov7740: remove an unused var

Fix this warning regression:
   drivers/media/i2c/ov7740.c: warning: variable 'ret' set but not used [-Wunused-but-set-variable]:  => 276:6

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/i2c/ov7740.c b/drivers/media/i2c/ov7740.c
index e1a44a1..01f5787 100644
--- a/drivers/media/i2c/ov7740.c
+++ b/drivers/media/i2c/ov7740.c
@@ -279,7 +279,7 @@
 	reg->val = val;
 	reg->size = 1;
 
-	return 0;
+	return ret;
 }
 
 static int ov7740_set_register(struct v4l2_subdev *sd,