rxrpc: Use consume_skb() rather than kfree_skb_reason()

Use consume_skb() rather than kfree_skb_reason().

Reported-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org