A shadow declaration of variable ret is being assigned a return error
status and this value is being lost when the error exit goto's jump
out of the local scope. This leads to an uninitalized error return value
in the outer scope being returned. Fix this by removing the inner scoped
declaration of variable ret.

Detected by CoverityScan, CID#1460380 ("Uninitialized scalar variable")

Fixes: fb45f436 ("media: v4l: async: Fix notifier complete callback error handling")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>