iwlwifi: remove deprecated broadcast filtering feature

This feature has been deprecated and should not be used anymore.  With
newer firmwares, namely *-67.ucode and above, trying to use it causes an
assertion failure in the FW, similar to this:

[Tue Jan 11 20:05:24 2022] iwlwifi 0000:04:00.0: 0x00001062 | ADVANCED_SYSASSERT

In order to prevent this feature from being used, remove it entirely
and get rid of the Kconfig option that
enables it (IWLWIFI_BCAST_FILTERING).

Fixes: cbaa6aee ("iwlwifi: bump FW API to 67 for AX devices")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215488


Cc: stable@vger.kernel.org # 5.16.x
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/iwlwifi.20220128144623.9241e049f13e.Ia4f282813ca2ddd24c13427823519113f2bbebf2@changeid