ath10k: Fix broken NULL func data frame status for 10.4

Older firmware with HTT delivers incorrect tx status for null func
frames to driver, but this fixed in 10.2 and 10.4 firmware versions.
Also this workaround results in reporting of incorrect null func status
for 10.4. Fix this is by introducing a firmware feature flag for 10.4
so that this workaround is skipped and proper tx status for null func
frames are reported

Signed-off-by: Tamizh chelvam <c_traja@qti.qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>