dri: get rid of LIBGL_SHOW_FPS

The same functionnality can be achieved using GALLIUM_HUD=stdout,fps (and for
now a fallback is doing this if LIBGL_SHOW_FPS=1 is used).

This removes one entry from the vtable and simplify dri3_handle_present_event.

Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20494>

src/loader/loader_dri3_helper.c

@@ -543,9 +543,6 @@ dri3_handle_present_event(struct loader_dri3_drawable *draw,
 #endif
          draw->last_present_mode = ce->mode;
 
-         if (draw->vtable->show_fps)
-            draw->vtable->show_fps(draw, ce->ust);
-
          draw->ust = ce->ust;
          draw->msc = ce->msc;
       } else if (ce->serial == draw->eid) {

src/loader/loader_dri3_helper.h

@@ -111,7 +111,6 @@ struct loader_dri3_vtable {
    __DRIcontext *(*get_dri_context)(struct loader_dri3_drawable *);
    __DRIscreen *(*get_dri_screen)(void);
    void (*flush_drawable)(struct loader_dri3_drawable *, unsigned);
-   void (*show_fps)(struct loader_dri3_drawable *, uint64_t);
 };
 
 #define LOADER_DRI3_NUM_BUFFERS (1 + LOADER_DRI3_MAX_BACK)