hikey: Add hardware/ti/wpan code to hikey device dir

The bluetooth userspace for hikey is related but newer
then the hardware/ti/wpan project in AOSP. Since we have
some hikey specific modifications, import the hikey version
into the device/linaro/hikey directory and tweak the build
to include it.

Code included from:
https://github.com/96boards/android_hardware_ti_wpan.git marshmallow-dev

Change-Id: I6246be43cb287bfd975b099a0e6508046e6d3add
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/device.mk b/device.mk
index a3cc8c2..7e6e8ac 100644
--- a/device.mk
+++ b/device.mk
@@ -74,7 +74,7 @@
                        vendor/linaro/hikey/mali/32bit/libGLES_mali.so:system/lib/egl/libGLES_mali.so
 
 # Include BT modules
-$(call inherit-product-if-exists, hardware/ti/wpan/ti-wpan-products.mk)
+$(call inherit-product-if-exists, devices/linaro/hikey/wpan/ti-wpan-products.mk)
 
 # Build boot_fat partition image
 $(call inherit-product-if-exists, device/linaro/hikey/boot_fat.mk)