i915/sync: Return early when calloc fails

Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/i915/intel_syncobj.c

@@ -51,6 +51,8 @@ intel_new_sync_object(struct gl_context *ctx, GLuint id)
    struct intel_sync_object *sync;
 
    sync = calloc(1, sizeof(struct intel_sync_object));
+   if (!sync)
+      return NULL;
 
    return &sync->Base;
 }