Use xorg_list_append for the DRM event list

We were adding entries at the start of the list, i.e. the list was
ordered from most recently added to least recently added. However, the
corresponding DRM events are generally expected to arrive in the same
order as they are queued, which means that amdgpu_drm_queue_alloc would
generally have to traverse the whole list to find the entry
corresponding to an arrived event. Fix this by adding entries at the end
of the list.

(Ported from radeon commit 3e24770b1b472fc15df56d06f5f04778c9db63dd)
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

src/amdgpu_drm_queue.c

@@ -105,7 +105,7 @@ amdgpu_drm_queue_alloc(xf86CrtcPtr crtc, ClientPtr client,
 	e->handler = handler;
 	e->abort = abort;
 
-	xorg_list_add(&e->list, &amdgpu_drm_queue);
+	xorg_list_append(&e->list, &amdgpu_drm_queue);
 
 	return e->seq;
 }

src/amdgpu_list.h

@@ -35,6 +35,13 @@
 #define xorg_list_del			list_del
 #define xorg_list_for_each_entry	list_for_each_entry
 #define xorg_list_for_each_entry_safe	list_for_each_entry_safe
+
+static inline void
+xorg_list_append(struct list *entry, struct list *head)
+{
+	__list_add(entry, head->prev, head);
+}
+
 #endif
 
 #endif /* _AMDGPU_LIST_H_ */