ath10k: fix VHT NSS calculation when STBC is enabled

[ Upstream commit 99f41b8e43b8b4b31262adb8ac3e69088fff1289 ]

When STBC is enabled, NSTS_SU value need to be accounted for VHT NSS
calculation for SU case.

Without this fix, 1SS + STBC enabled case was reported wrongly as 2SS
in radiotap header on monitor mode capture.

Tested-on: QCA9984 10.4-3.10-00047

Signed-off-by: Sathishkumar Muruganandam <murugana@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1597392971-3897-1-git-send-email-murugana@codeaurora.org


Signed-off-by: Sasha Levin <sashal@kernel.org>