wifi: rtw89: Fix rtw89_mac_power_switch() for USB

Clear some bits in some registers in order to allow RTL8851BU to power
on. This is done both when powering on and when powering off because
that's what the vendor driver does.

Also tested with RTL8832BU and RTL8832CU.

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/a39da939-d640-4486-ad38-f658f220afc8@gmail.com