wifi: rtl8xxxu: add hw crypto support for AP mode

Add a custom function for allocating entries in the sec cam. This allows
us to store multiple keys with the same keyidx.

The maximum number of sec cam entries for 8188f is 16 according to the
vendor driver. Add the number to rtl8xxxu_fileops, so that other chips
which might support more entries, can set a different number there.

Set the bssid as mac address for group keys instead of just using the
ethernet broadcast address and use BIT(6) in the sec cam ctrl entry
for differentiating them from pairwise keys like in the vendor driver.

Add the TXDESC_EN_DESC_ID bit and the hw_key_idx to tx
broadcast/multicast packets in AP mode.

Finally, allow the usage of rtl8xxxu_set_key() for AP mode.

Signed-off-by: Martin Kaistra <martin.kaistra@linutronix.de>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20231222101442.626837-20-martin.kaistra@linutronix.de