btrtl_vendor_read_reg16
ret = btrtl_vendor_read_reg16(hdev, RTL_CHIP_SUBVER, reg_val);
ret = btrtl_vendor_read_reg16(hdev, RTL_CHIP_REV, reg_val);
rc = btrtl_vendor_read_reg16(hdev, RTL_SEC_PROJ, reg_val);