netfilter: xt_qtaguid: Fix sockfd_put() call within spinlock

sockfd_put() risks sleeping.
So when doing a delete ctrl command, defer the sockfd_put() and
kfree() to outside of the spinlock.

Change-Id: I5f8ab51d05888d885b2fbb035f61efa5b7abb88a
Signed-off-by: JP Abgrall <jpa@google.com>