BACKPORT: net: xfrm: fix memory leak in xfrm_user_policy()

if xfrm_get_translator() failed, xfrm_user_policy() return without
freeing 'data', which is allocated in memdup_sockptr().

Bug: 254441685
Fixes: 96392ee5a13b ("xfrm/compat: Translate 32-bit user_policy from sockptr")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
(cherry picked from commit 48f486e13ffdb49fbb9b38c21d0e108ed60ab1a2)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I0744588549ae7ac9d11ffa6ceec4beb1962e6b4a