display: Reconcile display HALs

Make the display HALs compile with/without the Qualcomm BSP
specific features so they can work with pure AOSP.
Change-Id: I1ad7282c4fe1fe7e3309afb530a07735f165ffbe
diff --git a/common.mk b/common.mk
index ebfc8ec..78b48dd 100644
--- a/common.mk
+++ b/common.mk
@@ -32,8 +32,9 @@
 common_deps  :=
 kernel_includes :=
 
-#Kernel includes. Not being executed on JB+
+# Executed only on QCOM BSPs
 ifeq ($(call is-vendor-board-platform,QCOM),true)
+    common_flags += -DQCOM_BSP
     common_deps += $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr
     kernel_includes += $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr/include
 endif