wifi: rtw89: coex: Fix BT-info parsing for 5/6 GHz band & dual Bluetooth

The _update_bt_info() function always parsed BT-info for bt0 and used a
single raw_info buffer regardless of which BT device sent the packet or
which RF band it belongs to. This caused two bugs:

1. BT-info packets from bt1 were incorrectly parsed into bt0's state.

2. BT-info packets from 5/6 GHz BT (L1 bit7=1) overwrote the 2.4 GHz
   link_info and raw_info, breaking duplicate detection across bands.

Fix by adding the bid parameter to select bt0/bt1, detecting the 5/6 GHz
band flag (L1 bit7) to route packets into link_info_56g with a dedicated
raw_info_56g buffer, and updating the early-return mask to ignore bit7
when checking the length field.

Signed-off-by: Ching-Te Ku <ku920601@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260730060220.55844-3-pkshih@realtek.com