egl/dri2: Dispatch eglCopyBuffers by display, not driver

Add dri2_egl_display_vtbl::copy_buffers, set it for each
platform, and let egl_dri2 dispatch eglCopyBuffers to that.

This prepares for the EGL platform extensions.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 9ee4e12..3bf96ba 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -1073,6 +1073,14 @@
                                                    rects, n_rects);
 }
 
+static EGLBoolean
+dri2_copy_buffers(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *surf,
+                  EGLNativePixmapType target)
+{
+   struct dri2_egl_display *dri2_dpy = dri2_egl_display(dpy);
+   return dri2_dpy->vtbl->copy_buffers(drv, dpy, surf, target);
+}
+
 static EGLint
 dri2_query_buffer_age(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *surf)
 {
@@ -2110,6 +2118,7 @@
    dri2_drv->base.API.SwapInterval = dri2_swap_interval;
    dri2_drv->base.API.SwapBuffers = dri2_swap_buffers;
    dri2_drv->base.API.SwapBuffersWithDamageEXT = dri2_swap_buffers_with_damage;
+   dri2_drv->base.API.CopyBuffers = dri2_copy_buffers,
    dri2_drv->base.API.QueryBufferAge = dri2_query_buffer_age;
    dri2_drv->base.API.CreateImageKHR = dri2_create_image_khr;
    dri2_drv->base.API.DestroyImageKHR = dri2_destroy_image_khr;