[PATCH v1] arm: add call to cleanup_before_linux for go command

[Bryan Brattlof]

On April 30, 2025 thus sayeth Anshul Dalal:
> As discussed here[1], the go command causes undefined behavior when used
> for running custom OSes since the icache might hold outdated data. OSes
> usually also expect the MMU to be disabled upon execution.
> 
> Therefore this patch adds a call to cleanup_before_linux before we jump
> to the loaded program/os which disables both the caches and the MMU.
> This makes the go command's behavior consistent with riscv platforms.
> 

I know quite a few other OSes are beginning to use U-Boot (QNX, 
GreenHills or all the other RTOSes) each with their own requirements 
from the bootloader. I'm curious if we should make boot* a little more 
generic rather than abuse the 'go' command.

~Bryan