i40iw: Correct CQ arming

CQ is armed for solicited events only, ignoring other notification
flags. Correct this by arming for next and arming for solicited
event if IB_CQ_SOLICITED is set. Also protect CQ shadow area update
with spinlock.

Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>