drm/rockchip: vop2: use symmetric function pair vop2_{create,destroy}_crtcs

Let the function name vop2_create_crtcs reflect that the function creates
multiple CRTCS. Also, use a symmetric function pair to create and destroy
the CRTCs and the corresponding planes.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230124054706.3921383-5-michael.riesch@wolfvision.net