drm: rcar-du: lvds: Convert to RUNTIME_PM_OPS()

drm: rcar-du: lvds: Convert to RUNTIME_PM_OPS()

Convert the Renesas R-Car Display Unit LVDS driver from
SET_RUNTIME_PM_OPS() to RUNTIME_PM_OPS(), and pm_ptr().  This reduces
kernel size in case CONFIG_PM is disabled.  While DRM_RCAR_LVDS depends
on PM, the code may still serve as an example for new drivers.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/2264ff4f21a7e17384822e0efba176cf78ae184d.1756999823.git.geert+renesas@glider.be
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>