Add support for Build_external_kernelmodule.mk

The Android build infrastructure is transitioning to a new
mechansim for building external modules.
Starting from Taro(8450), update moto drivers to use that
mechanism.

Change-Id: Ic3640feabd6bd77334861d3f73082907ed88648b
Signed-off-by: a7301c <a7301c@motorola.com>
Reviewed-on: https://gerrit.mot.com/1941175
SME-Granted: SME Approvals Granted
SLTApproved: Slta Waiver
Tested-by: Jira Key
Reviewed-by: Zhenxin Xi <xizx@motorola.com>

AndroidKernelModule.mk

@@ -1,3 +1,7 @@
+ifeq ($(TARGET_BOARD_PLATFORM),taro)
+#Taro is using a new mechanisim to build kernel modules
+include device/qcom/common/dlkm/Build_external_kernelmodule.mk
+else
 ifneq (,$(findstring gki,$(KERNEL_DEFCONFIG)))
 #GKI product should use Qcom latest dlkm compile file
 include device/qcom/common/dlkm/AndroidKernelModule.mk
@@ -180,3 +184,4 @@ KBUILD_OPTIONS :=
 endif
 endif
 endif  #(findstring gki,$(KERNEL_DEFCONFIG))
+endif #($(TARGET_BOARD_PLATFORM),taro)