CONFIG_BT_MTK (not configurable)

modulename: btmtk.ko

configname: CONFIG_BT_MTK

Linux Kernel Configuration
└─>Networking support
└─>Bluetooth subsystem support
└─>Bluetooth device drivers
└─>BT_MTK
In linux kernel since version 5.2 (release Date: 2019-07-07)  
source code:
drivers/bluetooth/btmtk.c