wifi: rtw89: 8852bx: move BTC common code from 8852b to 8852b_common

The BT coexistence part of 8852B and 8852BT are similar, so move shared
code into common module.

Don't change logic for existing RTL8852BE.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240701014619.7300-1-pkshih@realtek.com