iwlwifi: fix unhandled interrupt when HW rfkill is on

This patch fixes unhandled interrupt when HW rfkill is on during
devices start up. The behavior changes, now open is successful even
when rfkill is on. This is to align with the situation when rfkill
is set on after opening.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>