egl/dri2: add image_loader_extension back into loader extensions for wayland

before commit f871946594129500a67c05a6d9fe99db54b4bb64
image_loader_extension was always present in dri2_dpy->extensions,
after that commit it is only present for render nodes.

Its removal broke partial render based on buffer age on (at least)
raspberry pi.

Fixes: f8719465941 "egl/dri2: rework dri2_egl_display::extensions storage"
Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/src/egl/drivers/dri2/platform_wayland.c b/src/egl/drivers/dri2/platform_wayland.c
index 395f1e1..fd4812a 100644
--- a/src/egl/drivers/dri2/platform_wayland.c
+++ b/src/egl/drivers/dri2/platform_wayland.c
@@ -1080,6 +1080,7 @@
 
 static const __DRIextension *dri2_loader_extensions[] = {
    &dri2_loader_extension.base,
+   &image_loader_extension.base,
    &image_lookup_extension.base,
    &use_invalidate.base,
    NULL,