mac80211: remove iwlwifi specific workaround NDPs of null_response

[ Upstream commit 744757e46bf13ec3a7b3507d17ab3faab9516d43 ]

Remove the remaining workaround that is not removed by the
commit e41eb3e408de ("mac80211: remove iwlwifi specific workaround
that broke sta NDP tx")

Fixes: 41cbb0f5 ("mac80211: add support for HE")
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://lore.kernel.org/r/20210623134826.10318-1-pkshih@realtek.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>