display: Ashmem: use MAP_POPULATE when mapping

If the flag is not used, it causes errors with
mapping the page tables in the kgsl driver

Change-Id: Iaa29eb764aff8a9af4b14fff9fdab60b50759e45

libgralloc/ashmemalloc.cpp

@@ -103,7 +103,7 @@ int AshmemAlloc::map_buffer(void **pBase, size_t size, int offset, int fd)
         return err;
 
     base = mmap(0, size, PROT_READ| PROT_WRITE,
-            MAP_SHARED, fd, 0);
+            MAP_SHARED|MAP_POPULATE, fd, 0);
     *pBase = base;
     if(base == MAP_FAILED) {
         LOGD("%s: Failed to map memory in the client: %s",