mac80211: remove iwlwifi specific workaround that broke sta NDP tx

Sending nulldata packets is important for sw AP link probing and detecting
4-address mode links. The checks that dropped these packets were apparently
added to work around an iwlwifi firmware bug with multi-TID aggregation.

Fixes: 41cbb0f5

 ("mac80211: add support for HE")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210619101517.90806-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>