Adding flag 'TARGET_DISABLE_DISPLAY'

Disabling compilation of display hal module if build flag
TARGET_DISABLE_DISPLAY is set to true.

Change-Id: I4ce621803601a1412e173224f41da6e5a219688c
CRs-Fixed: 2170353
diff --git a/Android.mk b/Android.mk
index 44393b0..a4d5687 100644
--- a/Android.mk
+++ b/Android.mk
@@ -1,3 +1,4 @@
+ifneq ($(TARGET_DISABLE_DISPLAY),true)
 sdm-libs := sdm/libs
 display-hals := include libqservice libqdutils $(sdm-libs)/utils $(sdm-libs)/core
 
@@ -15,3 +16,4 @@
     include $(call all-named-subdir-makefiles,$(display-hals))
 endif
 endif
+endif #TARGET_DISABLE_DISPLAY