This allows us to remove all the per-packet checks on x->encap->encap_type.
I've left the check in esp_input just in case someone adds a non-ESP encap
type in future.

However, printing a warning and then continuing is definitely wrong.
So expect a follow-up patch to drop the packet when encap_type is
unknown in esp_input.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@redhat.com>