[PATCH 3/4] arch: arm: mach-socfpga: Adjust a raw sectors for MMC loading of U-Boot from SPL

[Sune Brian]

> SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR on some boards, so this calculation is
> not universal.

Use setup like my handoff scripts for GEN5. xxx.mk
Preserve a offset variable on that.

https://patchwork.ozlabs.org/project/uboot/patch/20251119111653.456-1-briansune@gmail.com/

Flexible enough and allow user to control when required.
But please first wait the patch is completely pushed to mainstream first.
And also documentation can be done to explain a bit.

Brian