Currently the number of frames sent to the chip in a single USB Request
Block is limited only by the size of the TX buffer, which is 20 KiB.
Testing reveals that as many as 13 frames get aggregated. This is more
than what any of the chips would like to receive. RTL8822CU, RTL8822BU,
and RTL8821CU want at most 3 frames, and RTL8723DU wants only 1 frame
per URB.

RTL8723DU in particular reliably malfunctions during a speed test if it
receives more than 1 frame per URB. All traffic seems to stop. Pinging
the AP no longer works.

Fix this problem by limiting the number of frames sent to the chip in a
single URB according to what each chip likes.

Also configure RTL8822CU, RTL8822BU, and RTL8821CU to expect 3 frames
per URB.

RTL8703B may or may not be found in USB devices. Declare that it wants
only 1 frame per URB, just in case.

Tested with RTL8723DU and RTL8811CU.

Cc: stable@vger.kernel.org
Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/cb46ea35-7e59-4742-9c1f-01ceeaad36fb@gmail.com