return after freeing data element, instead of falling through, and using

the free'd element, and ultimate NULL deref of the failed allocation.

MFC after:	1 week

sys/dev/firewire/firewire.c

@@ -812,6 +812,7 @@ void fw_init(struct firewire_comm *fc)
 	fwb = (struct fw_bind *)malloc(sizeof (struct fw_bind), M_FW, M_NOWAIT);
 	if(fwb == NULL){
 		fw_xfer_free(xfer);
+		return;
 	}
 	xfer->act.hand = fw_vmaccess;
 	xfer->fc = fc;