aSIFSTime is 10us for 2GHz band and 16us for 5GHz and 6GHz bands.
Originally, it doesn't consider 6GHz band and use wrong value, so correct
it accordingly.

Cc: stable@vger.kernel.org
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://msgid.link/20240430020515.8399-1-pkshih@realtek.com