renderer: add renderer cleanup interface

this just tears down the EGL stuff for now

src/virglrenderer.c

@@ -253,6 +253,15 @@ void virgl_renderer_poll(void)
    vrend_renderer_check_fences();
 }
 
+void virgl_renderer_cleanup(void *cookie)
+{
+   if (use_egl_context) {
+      virgl_egl_destroy(egl_info);
+      egl_info = NULL;
+      use_egl_context = 0;
+   }
+}
+
 int virgl_renderer_init(void *cookie, int flags, struct virgl_renderer_callbacks *cbs)
 {
    if (!cookie || !cbs)

src/virglrenderer.h

@@ -146,6 +146,8 @@ struct virgl_renderer_resource_info {
 VIRGL_EXPORT int virgl_renderer_resource_get_info(int res_handle,
                                                   struct virgl_renderer_resource_info *info);
 
+VIRGL_EXPORT void virgl_renderer_cleanup(void *cookie);
+
 /* reset the rendererer - destroy all contexts and resource */
 VIRGL_EXPORT void virgl_renderer_reset(void);
 #endif