Spidernet another skb mem leak

Another skb leak in an error branch. Fix this by adding
call to dev_kfree_skb_irq() after moving to a more
appropriate spot.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: James K Lewis <jklewis@us.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>