ath10k: Fix length of wmi tlv command for protected mgmt frames

ath10k: Fix length of wmi tlv command for protected mgmt frames

The length of wmi tlv command for management tx send is calculated
incorrectly in case of protected management frames as there is addition
of IEEE80211_CCMP_MIC_LEN twice. This leads to improper behaviour of
firmware as the wmi tlv mgmt tx send command for protected mgmt frames
is formed wrongly.

Fix the length calculation of wmi tlv command for mgmt tx send in case
of protected management frames by adding the IEEE80211_CCMP_MIC_LEN only
once.

Tested HW: WCN3990
Tested FW: WLAN.HL.3.1-00784-QCAHLSWMTPLZ-1

Fixes: 1807da49733e "ath10k: wmi: add management tx by reference support over wmi"
Signed-off-by: Surabhi Vishnoi <svishnoi@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>