display: Use GRALLOC_USAGE_PROTECTED to indicate secure content

For secure content, use GRALLOC_USAGE_PROTECTED flag instead of
the obsolete flag GRALLOC_USAGE_PRIVATE_CP_BUFFER.

Change-Id: I69bf8cfd3a978fd472608beb44056e1bf55c1414
diff --git a/libgralloc/alloc_controller.cpp b/libgralloc/alloc_controller.cpp
index 669ea08..57c6bae 100644
--- a/libgralloc/alloc_controller.cpp
+++ b/libgralloc/alloc_controller.cpp
@@ -62,8 +62,7 @@
         return false;
     if(triedSystem)
         return false;
-    if(usage & (GRALLOC_HEAP_MASK | GRALLOC_USAGE_PROTECTED |
-                GRALLOC_USAGE_PRIVATE_CP_BUFFER))
+    if(usage & (GRALLOC_HEAP_MASK | GRALLOC_USAGE_PROTECTED))
         return false;
     if(usage & (GRALLOC_HEAP_MASK | GRALLOC_USAGE_PRIVATE_EXTERNAL_ONLY))
         return false;
@@ -124,7 +123,7 @@
     if(usage & GRALLOC_USAGE_PRIVATE_CAMERA_HEAP)
         ionFlags |= ION_HEAP(ION_CAMERA_HEAP_ID);
 
-    if(usage & GRALLOC_USAGE_PRIVATE_CP_BUFFER)
+    if(usage & GRALLOC_USAGE_PROTECTED)
         ionFlags |= ION_SECURE;
 
     // if no flags are set, default to