[media] vb2: don't free alloc context if it is ERR_PTR

Don't try to free a pointer containing an ERR_PTR().

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
1 file changed