st/xorg: Fix leave enter vt cycle in crtc code

src/gallium/state_trackers/xorg/xorg_crtc.c

@@ -307,8 +307,6 @@ xorg_crtc_cursor_destroy(xf86CrtcPtr crtc)
     if (crtcp->cursor_bo)
 	kms_bo_destroy(&crtcp->cursor_bo);
 #endif
-
-    xfree(crtcp);
 }
 
 /*
@@ -320,11 +318,12 @@ crtc_destroy(xf86CrtcPtr crtc)
 {
     struct crtc_private *crtcp = crtc->driver_private;
 
-    if (crtcp->cursor_tex)
-	pipe_texture_reference(&crtcp->cursor_tex, NULL);
+    xorg_crtc_cursor_destroy(crtc);
 
     drmModeFreeCrtc(crtcp->drm_crtc);
+
     xfree(crtcp);
+    crtc->driver_private = NULL;
 }
 
 static const xf86CrtcFuncsRec crtc_funcs = {