Remove old GrFlushFlag for cpu sync which isn't used anymore.

Test: manual
Change-Id: Ib362f228c18b6c452e66debe6f6f076451670cd7
diff --git a/libs/hwui/renderthread/CacheManager.cpp b/libs/hwui/renderthread/CacheManager.cpp
index dc1612c..b57dee4 100644
--- a/libs/hwui/renderthread/CacheManager.cpp
+++ b/libs/hwui/renderthread/CacheManager.cpp
@@ -122,9 +122,7 @@
 
     // We must sync the cpu to make sure deletions of resources still queued up on the GPU actually
     // happen.
-    GrFlushInfo info;
-    info.fFlags = kSyncCpu_GrFlushFlag;
-    mGrContext->flush(info);
+    mGrContext->flush({});
     mGrContext->submit(true);
 }