[undi] Include PXENV_GET_IFACE_INFO's ServiceFlags in debug output

src/arch/i386/drivers/net/undinet.c

 				   &undi_iface,
 				   sizeof ( undi_iface ) ) ) != 0 )
 		goto err_undi_get_iface_info;
-	DBGC ( undinic, "UNDINIC %p has type %s and link speed %d\n",
-	       undinic, undi_iface.IfaceType, undi_iface.LinkSpeed );
+	DBGC ( undinic, "UNDINIC %p has type %s, speed %d, flags %08x\n",
+	       undinic, undi_iface.IfaceType, undi_iface.LinkSpeed,
+	       undi_iface.ServiceFlags );
 	if ( strncmp ( ( ( char * ) undi_iface.IfaceType ), "Etherboot",
 		       sizeof ( undi_iface.IfaceType ) ) == 0 ) {
 		DBGC ( undinic, "UNDINIC %p Etherboot 5.4 workaround enabled\n",