wifi: rtw88: pci: Change queue datatype to enum rtw_tx_queue_type

This makes it easier to understand which values are allowed for the
"queue" variable when using the enum instead of an u8.

Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230204233001.1511643-3-martin.blumenstingl@googlemail.com