Revert "xfrm: Fix unregister netdevice hang on hardware offload."

This reverts commit d5f53edd which is
commit 07b87f9e upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Id426f42171cef3de7f91f5c29004fc9871f1e5a1
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>