Generic Bluetooth HAL for standard Linux hci interface

This acts as common interface for bluetooth devices (including
USB ones) using the standard Linux bluetooth hci interface.

Much of this code is pulled from hardware/interface/bluetooth
and system/bt/vendor_libs/linux.

Original code used from "system/bt/vendor_libs/linux" was from:
Samuel Ortiz <sameo@linux.intel.com>
Cristian Iorga <cristian.iorga@intel.com>
Pavlin Radoslavov <pavlin@google.com>
Jakub Pawlowski <jpawlowski@google.com>
Myles Watson <mylesgw@google.com>

Orginal code taken from hardware/interface/bluetooth was
contributed by:
Myles Watson <mylesgw@google.com>
Zach Johnson <zachoverflow@google.com>
Treehugger Robot <treehugger-gerrit@google.com>

Tested:
Hikey + on board bluetooth and Hikey + USB bluetooth dongle

Change-Id: I03da10cadfae6ffb298cfccc98e3337ab7db1967
Signed-off-by: Satish Patel <satish.patel@linaro.org>
[jstultz: Migrated code back to system/bt/vendor_libs/linux/.
 Included required sepolicy changes. Reworded and simplified
 commit message. ]
Signed-off-by: John Stultz <john.stultz@linaro.org>