Revert "xfrm: add SA information to the offloaded packet"

This reverts commit e7cd191f.

While supporting xfrm interfaces in the packet offload API
is needed, this patch does not do the right thing. There are
more things to do to really support xfrm interfaces, so revert
it for now.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>