libweston-desktop: Fix configure event for already well-sized surfaces

Even if the surface size is already correct, we need to store the
configured size in case some other state change triggers a configure
event.

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Arnaud Vrac <avrac@freebox.fr>
3 files changed