wifi: iwlwifi: add support for a wiphy_work rx handler

wifi: iwlwifi: add support for a wiphy_work rx handler

The wiphy_work infra ensures that the entire worker will run
with the wiphy mutex. It is useful to have RX handlers
running as a wiphy_work, when we don't want the handler to
run in parallel with mac80211 work (to avoid races).

For example - BT notification can disable eSR starting from the next
patch.
In ieee80211_set_active_links we first check that eSR is
allowed, (drv_can_activate_links) and then activate it.
If the BT notif was received after drv_can_activate_links
(which returned true), and before the activation - eSR will be
activated when it shouldn't.
If BT notif is handled with the wiphy mutex, it can't run in
parallel to ieee80211_set_active_links, which also holds that
mutex.

Add the necessary infrastructure here, for use in the next commit.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240123200528.ce83d16cdec8.I35ef53fa23f58b9ec17924099238b61deafcecd7@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>