libqservice: Change the permission for SCREEN_REFRESH

Change the SCREEN_REFRESH permission from AID_GRAPHICS to AID_SYSTEM.

Change-Id: I8d732282df481695d8241e3087725784825b756d
diff --git a/libqservice/IQService.cpp b/libqservice/IQService.cpp
index 6c6f7b6..53b05e3 100644
--- a/libqservice/IQService.cpp
+++ b/libqservice/IQService.cpp
@@ -133,7 +133,7 @@
         } break;
         case SCREEN_REFRESH: {
             CHECK_INTERFACE(IQService, data, reply);
-            if(callerUid != AID_GRAPHICS) {
+            if(callerUid != AID_SYSTEM) {
                 ALOGE("display.qservice SCREEN_REFRESH access denied: \
                       pid=%d uid=%d process=%s",callerPid,
                       callerUid, callingProcName);