drm/rockchip: vop: Use cleanup helper directly as destroy funcs

vop_plane_destroy and vop_crtc_destroy are plain wrappers around
drm_plane_cleanup and drm_crtc_cleanup. Use them directly as plane and
crtc funcs to closer match VOP2 driver.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230621223311.2239547-3-jonas@kwiboo.se