drm/rockchip: vop2: Add debugfs support

/sys/kernel/debug/dri/vop2/summary:  dump vop display state
/sys/kernel/debug/dri/vop2/regs: dump whole vop registers
/sys/kernel/debug/dri/vop2/active_regs: only dump the registers of
activated modules

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Tested-by: Michael Riesch <michael.riesch@wolfvision.net> # on RK3568
Tested-by: Detlev Casanova <detlev.casanova@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20241214081719.3330518-2-andyshrk@163.com