arm: sc5xx: Enable BOOTSTD_DEFAULTS

[ukleinek]

This setting implies various config knobs that are "commonly needed to support a good selection of booting methods." Among them is CONFIG_SUPPORT_RAW_INITRD which is convenient for booting a Debian installer.

[ozan956]

Hey @ukleinek,

Can you sign the commit please
https://github.com/analogdevicesinc/u-boot/actions/runs/30635738326/job/91172768680?pr=136#step:8:39

It should be failing but apparently its not.

[pamolloy]

I think it is fine to just enable this for 64-bit for now, and not for 32-bit given resource constraints. We just need to remember to do it for SC846 as a separate commit. So maybe hold off until the SC846 is merged and enable for both.

@ukleinek just so you know the process, once it is approved here you can submit the patch upstream (note the mailing list is now at u-boot-project.org), add a link to here (lore is preferred, although that recently broke with the domain migration), and once applied upstream then cherry-pick -x the upstream commit here and we'll merge it.