i965: Add extra null check in intel_bufferobj_alloc()

Check calloc returned requested memory.

Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>

src/mesa/drivers/dri/i965/intel_buffer_objects.c

@@ -136,6 +136,9 @@ static struct gl_buffer_object *
 intel_bufferobj_alloc(struct gl_context * ctx, GLuint name, GLenum target)
 {
    struct intel_buffer_object *obj = CALLOC_STRUCT(intel_buffer_object);
+   if (!obj) {
+      _mesa_error_no_memory(__func__);
+   }
 
    _mesa_initialize_buffer_object(ctx, &obj->Base, name, target);