CONFIG_BT_HCIBTUSB selects CONFIG_BT_INTEL. That causes CONFIG_BT_INTEL
to be built-in instead of being built as a kernel module.
When the driver is built-in, loading firmware fails during early boot
with the following error message:
[ 1.058941] bluetooth hci0: Direct firmware load for intel/ibt-17-16-1.sfi failed with error -2
Make sure the driver is built as a module which should fix firmware
loading.