rockchip/drm: vop2: add support for gamma LUT

Add support for gamma LUT in VOP2 driver. The implementation was inspired
by one found in VOP1 driver. Blue and red channels in gamma LUT register
write were swapped with respect to how gamma LUT values are written in
VOP1. Gamma LUT port selection was added before the write of new gamma LUT
table.

If the current SoC is rk356x, check if no other CRTC has gamma LUT enabled
in atomic_check (only one video port can use gamma LUT at a time) and
disable gamma LUT before the LUT table write.

If the current SoC isn't rk356x, "seamless" gamma lut update is performed
similarly to how it was done in the case of RK3399 in VOP1[1]. In seamless
update gamma LUT disable before the write isn't necessary, check if no
other CRTC has gamma LUT enabled is also not necessary, different register
is being used to select gamma LUT port[2] and after setting DSP_LUT_EN bit,
GAMMA_UPDATE_EN bit is set[3].

Gamma size is set and drm color management is enabled for each video port's
CRTC except ones which have no associated device.

Patch was tested on RK3566 (Pinetab2). When using userspace tools
which set eg. constant color temperature no issues were noticed. When
using userspace tools which adjust eg. color temperature the slight screen
flicker is visible probably because of gamma LUT disable needed in the
case of RK356x before gamma LUT write.

Compare behaviour of eg.:
```
gammastep -O 3000
```

To eg.:
```
gammastep -l 53:23 -t 6000:3000
```

In latter case color temperature is slowly adjusted at the beginning which
causes screen to slighly flicker. Then it adjusts every few seconds which
also causes slight screen flicker.

[1] https://lists.infradead.org/pipermail/linux-rockchip/2021-October/028132.html
[2] https://lore.kernel.org/linux-rockchip/48249708-8c05-40d2-a5d8-23de960c5a77@rock-chips.com/
[3] https://github.com/radxa/kernel/blob/linux-6.1-stan-rkr1/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c#L3437



Helped-by: Daniel Stone <daniel@fooishbar.org>
Helped-by: Dragan Simic <dsimic@manjaro.org>
Helped-by: Diederik de Haas <didi.debian@cknow.org>
Helped-by: Andy Yan <andy.yan@rock-chips.com>
Signed-off-by: Piotr Zalewski <pZ010001011111@proton.me>
Reviewed-by: Andy Yan <andyshrk@163.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20241101185545.559090-3-pZ010001011111@proton.me