RFC: removing redundant checks in ether_input_internal()

[Luigi Rizzo]

if_ethersubr.c :: ether_input_internal() is only called as follows:

    static void
    ether_nh_input(struct mbuf *m)
    {

        ether_input_internal(m->m_pkthdr.rcvif, m);
    }

hence the following checks in the body are unnecessary:

        if (m->m_pkthdr.rcvif == NULL) {
                if_printf(ifp, "discard frame w/o interface pointer\n");
                ifp->if_ierrors++;
                m_freem(m);
                return;
        }
    #ifdef DIAGNOSTIC
        if (m->m_pkthdr.rcvif != ifp) {
                if_printf(ifp, "Warning, frame marked as received on %s\n",
                        m->m_pkthdr.rcvif->if_xname);
        }
    #endif

Any objection if i remove them ?

	cheers
	luigi