[IRDA]: Missing allocation result check in irlap_change_speed().

The skb allocation may fail, which can result in a NULL pointer dereference
in irlap_queue_xmit().

Coverity CID: 434.
Signed-off-by: Florin Malita <fmalita@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/irda/irlap.c

@@ -884,7 +884,8 @@ static void irlap_change_speed(struct irlap_cb *self, __u32 speed, int now)
 	if (now) {
 		/* Send down empty frame to trigger speed change */
 		skb = dev_alloc_skb(0);
-		irlap_queue_xmit(self, skb);
+		if (skb)
+			irlap_queue_xmit(self, skb);
 	}
 }