display: hal: Conditionally build HAL modules

* QTI composer service and sdmcore have proprietary header dependency
on Pixelworks projects.
* Hence, allow the modules to be hidden when proprietary headers
are not present in source tree.

Issue: FP4-INT#3
Change-Id: I0c3c7bc57f63eb576a27c4a735767b49c0924be9
diff --git a/composer/Android.mk b/composer/Android.mk
index 461396c..3de43ad 100644
--- a/composer/Android.mk
+++ b/composer/Android.mk
@@ -1,3 +1,4 @@
+ifeq ($(TARGET_HAS_PROPRIETARY_HEADERS), true)
 LOCAL_PATH := $(call my-dir)
 
 include $(LOCAL_PATH)/../common.mk
@@ -77,3 +78,4 @@
 endif
 
 include $(BUILD_EXECUTABLE)
+endif
diff --git a/sdm/libs/core/Android.mk b/sdm/libs/core/Android.mk
index 798585d..95e5934 100644
--- a/sdm/libs/core/Android.mk
+++ b/sdm/libs/core/Android.mk
@@ -1,3 +1,4 @@
+ifeq ($(TARGET_HAS_PROPRIETARY_HEADERS), true)
 LOCAL_PATH := $(call my-dir)
 include $(CLEAR_VARS)
 include $(LOCAL_PATH)/../../../common.mk
@@ -49,3 +50,4 @@
 endif
 
 include $(BUILD_SHARED_LIBRARY)
+endif