[PATCH linux dev-4.19] ARM: dts: palmetto: Fix flash_memory region

[Lei YU]

> > The flash_memory region was incorrect and exceeds AST2400's RAM range.
> > Fix it by putting it before coldfire region, and aligned with 32MiB.
>
> We've had a patch to do this in patchwork for some time now:
>
> https://patchwork.ozlabs.org/patch/879522/
>
> We can't do that as it breaks booting, as the FIT loading will
> (sometimes) place the initrd or dtb in the reserved region, and this
> stops Linux from being able to map it, causing boot to fail.
>
> We need to fix that bug before we can resolve this issue. There is a
> u-boot environment variable that can be set that stops anything being
> loaded too high. The proper fix is probably to make u-boot's FIT
> loader aware of the reserved mappings and not put things there. Other
> suggestions are welcome.

This patch puts the window a bit lower, 0x5c000000 instead of 0x5e000000,
and from my testing it does not break booting.