UPSTREAM: xfrm: fix gro_cells leak when remove virtual xfrm interfaces

The device gro_cells has been initialized, it should be freed,
otherwise it will be leaked

Bug: 254441685
Fixes: f203b76d ("xfrm: Add virtual xfrm interfaces")
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
(cherry picked from commit 4da40259)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ia796adc27873089a1158595bd479f99b5719932a