wifi: rtl8xxxu: Support USB RX aggregation for the newer chips

The driver can receive several frames in the same USB transfer.
Add the code to handle this in rtl8xxxu_parse_rxdesc24(), even though
currently all the relevant chips send only one frame per USB transfer
(RTL8723BU, RTL8192EU, RTL8188FU, RTL8710BU).

This was tested with RTL8188FU, RTL8192EU, RTL8710BU, and RTL8192FU.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/16d2d1ff-6438-10c9-347f-6e14dd358ccf@gmail.com