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

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