rk35xx: Remove legacy kernel target from board configs

[ColorfulRhino]

Description

As discussed in #6835
Deprecate legacy, but only remove from board configs for now. Print a warning, the whole branch is slated for removal.

@efectn Please have a look at Opi5, there was some functions in the board config uboot_add_sata_target

@amazingfate @igorpecovnik I think it would be best to change the default branch in the vendor kernel repo to the new 6.1-rk3 https://github.com/armbian/linux-rockchip what do you think?

GitHub issue reference: #6835
Jira reference number AR-2394

How Has This Been Tested?

• ./compile.sh kernel BOARD=nanopi-r6s BRANCH=legacy BUILD_DESKTOP=no BUILD_MINIMAL=no EXPERT=yes KERNEL_CONFIGURE=no RELEASE=trixie -> New deprecation warning appears

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[amazingfate]

I think it would be best to change the default branch in the vendor kernel repo to the new 6.1-rk3 https://github.com/armbian/linux-rockchip what do you think?

I just changed the default branch to rkr1. rkr3 is still wip and the branch there is not usable.

[amazingfate]

Legacy 5.10 kernel still has some advantages, for example ubuntu 22.04 ships ffmpeg 4.4, and patched ffmpeg 4.4 won't work with 6.1 kernel because rk dropped its dma_heap driver. So people have to choose between 5.10 kernel with ubuntu jammy and 6.1 kernel with ubuntu noble.

Jammy is just a release from two years ago, and I have marked it as dead lol. There should be no active development on it with rockchip's mpp ecosystem.

While I'm okay with deleting legacy in board config, as long as users can build it by their own choice.

[ColorfulRhino]

Legacy 5.10 kernel still has some advantages, for example ubuntu 22.04 ships ffmpeg 4.4, and patched ffmpeg 4.4 won't work with 6.1 kernel because rk dropped its dma_heap driver. So people have to choose between 5.10 kernel with ubuntu jammy and 6.1 kernel with ubuntu noble.

Jammy is just a release from two years ago, and I have marked it as dead lol. There should be no active development on it with rockchip's mpp ecosystem.

I see, this is why it's not fully removed yet.

Offtopic: I understand that the stability for an older Ubuntu LTS is nice for certain server applications since the environment doesn't change. For newly built images/systems though, I can not imagine why anyone would choose to install 22.04 over 24.04 nowadays since 24.04 is the new stable release (not some testing release). New features, updated packages, more support for up-to-date stuff, ...
But then again, this is just my personal way of thinking since I have always used rolling release distros. I just love being up-to-date 😄

While I'm okay with deleting legacy in board config, as long as users can build it by their own choice.

Yes, people can setill build it manually until legacy is removed completely (maybe in some months or half a year we can re-evalute removal, or when integrating rk35xx into rockchip64 whenever that may be).