modesetting: Remove unnecessary fb addition from drmmode_xf86crtc_resize

drmmode_set_mode_major() is the only user of drmmode->fb_id and will
create it if necessary.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>

hw/xfree86/drivers/modesetting/drmmode_display.c

@@ -1697,7 +1697,6 @@ drmmode_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
         drmmode_crtc = xf86_config->crtc[0]->driver_private;
     drmmode_ptr drmmode = drmmode_crtc->drmmode;
     drmmode_bo old_front;
-    Bool ret;
     ScreenPtr screen = xf86ScrnToScreen(scrn);
     uint32_t old_fb_id;
     int i, pitch, old_width, old_height, old_pitch;
@@ -1719,8 +1718,9 @@ drmmode_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
     old_width = scrn->virtualX;
     old_height = scrn->virtualY;
     old_pitch = drmmode_bo_get_pitch(&drmmode->front_bo);
-    old_fb_id = drmmode->fb_id;
     old_front = drmmode->front_bo;
+    old_fb_id = drmmode->fb_id;
+    drmmode->fb_id = 0;
 
     if (!drmmode_create_bo(drmmode, &drmmode->front_bo,
                            width, height, scrn->bitsPerPixel))
@@ -1732,13 +1732,6 @@ drmmode_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
     scrn->virtualY = height;
     scrn->displayWidth = pitch / cpp;
 
-    ret = drmModeAddFB(drmmode->fd, width, height, scrn->depth,
-                       scrn->bitsPerPixel, pitch,
-                       drmmode_bo_get_handle(&drmmode->front_bo),
-                       &drmmode->fb_id);
-    if (ret)
-        goto fail;
-
     if (!drmmode->gbm) {
         new_pixels = drmmode_map_front_bo(drmmode);
         if (!new_pixels)