build: core: include platform helper macros in target makefiles

* These are now needed sooner than we had been importing them
  in android_build. This ensures they'll be imported before
  their macros are needed.

* Modify for omni
  - drop MTK bits

Change-Id: I5ba29c32fff38d33728c2ba5cb9d05832369f39c
diff --git a/build/core/qcom_target.mk b/build/core/qcom_target.mk
index 980e17b..d0bd6bb 100644
--- a/build/core/qcom_target.mk
+++ b/build/core/qcom_target.mk
@@ -1,3 +1,6 @@
+# Bring in Qualcomm helper macros
+include vendor/omni/build/core/qcom_utils.mk
+
 # Target-specific configuration
 ifeq ($(BOARD_USES_QCOM_HARDWARE),true)
     qcom_flags := -DQCOM_HARDWARE