Move BTM_IS_BRCM_CONTROLLER to end usecase

From: stack/btm/security_device_record.h
Into: stack/l2cap/l2c_utils.cc

Towards readable code

Bug: 163134718
Tag: #refactor
Test: compile & verify basic functions working
Test: act.py -tc BleCocTest

Change-Id: I4c69507efdabc35d7e7f393ac3e92481a0666d98