wifi: rtw89: declare EXT NSS BW of VHT capability

According to IEEE Std. 802.11, it defines:
Indicates whether the STA is capable of interpreting the Extended NSS BW
Support subfield of the VHT Capabilities Information field.

Some AP such as TP-LINK BE19000 would check it for bandwidth settings, so
causes 80MHz rate when associating on 160 MHz bandwidth. Declare this
capability to yield expected result.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240112062640.36922-5-pkshih@realtek.com