overlay: Secure playback add missing flag.

Add the missing GRALLOC_USAGE_PRIVATE_CP_BUFFER while allocating secure memory
Change the O_SYNC to O_DSYNC flag.

Change-Id: Ida014018be111a7904ff07c206a673b2abf52d05

libgralloc/ionalloc.cpp

@@ -85,8 +85,7 @@ int IonAlloc::alloc_buffer(alloc_data& data)
     if(data.uncached) {
         // Use the sync FD to alloc and map
         // when we need uncached memory
-        // XXX: Change O_SYNC to O_DSYNC when available in bionic
-        ionSyncFd = open(ION_DEVICE, O_RDONLY|O_SYNC);
+        ionSyncFd = open(ION_DEVICE, O_RDONLY|O_DSYNC);
         if(ionSyncFd < 0) {
             ALOGE("%s: Failed to open ion device - %s",
                   __FUNCTION__, strerror(errno));

liboverlay/overlayMem.h

@@ -122,6 +122,7 @@ inline bool OvMem::open(uint32_t numbufs,
     if(isSecure) {
         allocFlags |= GRALLOC_USAGE_PRIVATE_MM_HEAP;
         allocFlags |= GRALLOC_USAGE_PRIVATE_DO_NOT_MAP;
+        allocFlags |= GRALLOC_USAGE_PRIVATE_CP_BUFFER;
     }
 
     int err = 0;