yam: fix a memory leak in yam_siocdevprivate()

yam: fix a memory leak in yam_siocdevprivate()

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit?id=729e54636b3ebefb77796702a5b1f1ed5586895e
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2022-24959

[ Upstream commit 29eb31542787e1019208a2e1047bb7c76c069536 ]

ym needs to be free when ym->cmd != SIOCYAMSMCS.

Fixes: 0781168e23a2 ("yam: fix a missing-check bug")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name yam-fix-a-memory-leak-in-yam_siocdevprivate.patch