ath10k: Fix the wrong updation of BW in tx_stats debugfs entry

Currently, the bandwidth is updated wrongly in BW table in tx_stats
debugfs per sta as there is difference in number of bandwidth type
in mac80211 and driver stats table. This leads to bandwidth getting
updated at wrong index in bandwidth table in tx_stats.

Fix this index mismatch between mac80211 and driver stats table (BW table)
by making the number of bandwidth type in driver compatible with mac80211.

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

Fixes: a904417f ("ath10k: add extended per sta tx statistics support")
Signed-off-by: Surabhi Vishnoi <svishnoi@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>