display: Fix path to vendor/qcom/opensource

QC_OPEN_PATH is not defined anywhere, so display_config_version
was not being set properly, resulting in broken hwcomposer.

Change-Id: I29b2e902af6a157c863408ed5f60be115caa859f
diff --git a/common.mk b/common.mk
index 83c4f1c..c738448 100644
--- a/common.mk
+++ b/common.mk
@@ -1,13 +1,13 @@
 #Common headers
 display_top := $(call my-dir)
 display_config_version := $(shell \
-    if [ -d "$(QC_OPEN_PATH)/interfaces/vendor/display/config/1.1" ];\
+    if [ -d "$(TOP)/vendor/qcom/opensource/interfaces/display/config/1.1" ];\
     then echo DISPLAY_CONFIG_1_1; fi)
 display_config_version := $(shell \
-    if [ -d "$(QC_OPEN_PATH)/interfaces/vendor/display/config/1.2" ];\
+    if [ -d "$(TOP)/vendor/qcom/opensource/interfaces/display/config/1.2" ];\
     then echo DISPLAY_CONFIG_1_2; fi)
 display_config_version := $(shell \
-    if [ -d "$(QC_OPEN_PATH)/interfaces/vendor/display/config/1.3" ];\
+    if [ -d "$(TOP)/vendor/qcom/opensource/interfaces/display/config/1.3" ];\
     then echo DISPLAY_CONFIG_1_3; fi)
 
 #Common C flags