If the skb allocation fails, the current error path calls
dev_kfree_skb_irq() with a NULL argument.  Also, 'err' is not being used.

Coverity CID: 275.
Signed-off-by: NFlorin Malita <fmalita@gmail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>