enic: use spin_lock(wq_lock) instead of spin_lock_irqsave(wq_lock)

All the access to wq has been moved out of hardirq context. We no longer need to
use spin_lock_irqsave.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>