Igor,
I figured out the problem which I was facing. There was a missing conf file which is needed for the BT to work. I am putting the contents below for future use if anyone needs it.
File: AndroidSrc/hardware/broadcom/libbt/conf/fsl/evk_8mq/bt_vendor.conf
# UART device port where Bluetooth controller is attached
UartPort = /dev/ttyUSB0
# Firmware patch file location
FwPatchFilePath = /vendor/firmware/brcm/
FwPatchFileName = BCM4349B1.hcd
And add this in the File: AndroidSrc/device/fsl/imx8/evk_8mq.mk
PRODUCT_COPY_FILES += hardware/broadcom/libbt/conf/fsl/evk_8mq/bt_vendor.conf:system/etc/bluetooth/bt_vendor.conf
This change worked for me.