fix build

Change-Id: I3fbc17ced9d51aaad513661aa296c41a6d0c4bc0
diff --git a/shared/OpenglCodecCommon/goldfish_address_space_android.impl b/shared/OpenglCodecCommon/goldfish_address_space_android.impl
index a4ebac2..9b0c744 100644
--- a/shared/OpenglCodecCommon/goldfish_address_space_android.impl
+++ b/shared/OpenglCodecCommon/goldfish_address_space_android.impl
@@ -477,7 +477,7 @@
 
     if (res == MAP_FAILED) {
         ALOGE("%s: failed to map. errno: %d\n", __func__, errno);
-        return nullptr;
+        return 0;
     }
 
     return (void*)(((char*)res) + (uintptr_t)(pgoff & (PAGE_SIZE - 1)));