drm/panel: lvds: Remove unused members from main structure

Since commit 03fa454b ("drm/panel: lvds: Simplify mode parsing"),
the width and height members of struct panel_lvds are no longer used.
Remove them.  No functional change.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Link: https://lore.kernel.org/r/20250829-panel-lvds-remove-width-height-v1-1-acecf0c84dc4@nxp.com