wifi: rtw89: usb: Rx aggregation for RTL8832CU/RTL8851BU

wifi: rtw89: usb: Rx aggregation for RTL8832CU/RTL8851BU

USB RX Aggregation is a performance optimization technique used
in USB network devices to increase throughput.

Instead of sending every received network packet to the host computer
individually, the device hardware groups multiple smaller packets
into a single, large USB Bulk Transfer.

 * toAP/toNB use iperf3 respectively.

With Cisco BE6000 - iperf3 tcp 10 pair (to another NB)

[6G 160Mhz]:

 RTL8832CU-USB3.0
       before   after
 TX    941      941
 RX    847      919

 RTL8832CU-USB2.0
       before   after
 TX    293      286
 RX    342      356

[5G 80Mhz]:

 RTL8832CU-USB3.0
       before   after
 TX    864      877
 RX    864      902

 RTL8832CU-USB2.0
       before   after
 TX    279      271
 RX    327      349

 RTL8851BU
       before   after
 TX    115      114
 RX    295      306

Signed-off-by: Shin-Yi Lin <isaiah@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260312055724.12177-1-pkshih@realtek.com