Support PicoCORE IMX8MP with a buildroot based release

Can we support the PicoCORE based on a IMX8MP also with buildroot.

I already set up a working configuration to run the board with a minimal image and created a pull request under [1].

Would be great to have buildroot also for picocore imx8mp.

Thanks.

[1]:

https://github.com/FSEmbedded/buildroot-fus/pull/1