wifi: rtw89: Lower the timeout in rtw89_fw_read_c2h_reg() for USB

This read_poll_timeout_atomic() with a delay of 1 µs and a timeout of
1000000 µs can take ~250 seconds in the worst case because sending a
USB control message takes ~250 µs.

Lower the timeout to 4000 for USB in order to reduce the maximum polling
time to ~1 second.

This problem was observed with RTL8851BU while suspending to RAM with
WOWLAN enabled. The computer sat for 4 minutes with a black screen
before suspending.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/09313da6-c865-4e91-b758-4cb38a878796@gmail.com