iwlwifi: don't enable all interrupts on resuming

Enabling the RF-kill interrupt is sufficient for getting
RF-kill notifications, and no other interrupt is needed
as the device isn't functional when suspended and will be
restarted/reconfigured when mac80211 resumes it later.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>