wifi: iwlwifi: remove disable_dummy_notification

This struct member is read-only, so can never change away
from the default value of zero. Remove the code that's in
an if on the value, since it's effectively dead code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230620125813.e7c96d0aa805.I5b158ce15e48393d2896c0bff9f644d983f0e92d@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>