When unreserving caps check if there is too mamy available caps
in the ->caps_list, if so release unreserved caps.
Signed-off-by: NChengguang Xu <cgxu519@icloud.com>
Reviewed-by: N"Yan, Zheng" <zyan@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>