xfrm: Fix memleak on xfrm state destroy

xfrm: Fix memleak on xfrm state destroy

We leak the page that we use to create skb page fragments
when destroying the xfrm_state. Fix this by dropping a
page reference if a page was assigned to the xfrm_state.

Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Reported-by: JD <jdtxs00@gmail.com>
Reported-by: Paul Wouters <paul@nohats.ca>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
BugLink: https://bugs.launchpad.net/bugs/1853197
(cherry picked from commit 86c6739eda7d2a03f2db30cbee67a5fb81afa8ba)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Sultan Alsawaf <sultan.alsawaf@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>