iwlwifi: Tell the ucode immediately when association state changes

When we get a state change of associated or not, we need to tell the
ucode via the RX_ON command using the filter flags.  This will prevent
the ucode from sending any packets when not associated, specifically not
sending NULL QOS packets after a deauthentication which causes the AP to
repeatedly send deauth's in some situations.

Signed-off-by: Jay Sternberg <jay.e.sternberg@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>