Enable Nallino support for U-Boot in machine layer

This MR just adds support of Nallino board to U-Boot from Yocto Kirstone.

Refer to https://secogroup.atlassian.net/browse/YT-212 Nallino: add U-Boot support for the description of the task.

These patches were ported from Yocto Rocko release: https://support.garz-fricke.com/projects/Nallino/Linux-Yocto/Releases/yocto-rocko-nallino-overview.html

MR for machine layer: seco-ne/yocto/layers/meta-seconorth-machine!592 (merged)

Note: there are 3 active MR groups for U-Boot right now. And although they are not dependent on each other, if one of them is merged, other two needs to be rechecked and probably updated. Here is a full list of MRs:

Santino support:

• !233 (merged)
• seco-ne/yocto/layers/meta-seconorth-machine!600 (merged)

Nallino support:

• seco-ne/yocto/layers/meta-seconorth-machine!592 (merged)
• !227 (merged)

FNGS corruption:

• !230