[PATCH] doc: Remove README.sha1 file

[Tom Rini]

On Wed, 22 Nov 2023 22:57:07 +0000, Peter Robinson wrote:

> The contents of README.sha1 only refer to process around verification
> of the pcs440ep board firmware in flash. The device was removed in
> commit 242836a893ae ("powerpc: ppc4xx: remove pcs440ep support") in
> 2015 so this readme isn't really relevant anymore so can be removed.
> 
> 

Applied to u-boot/master, thanks!

-- 
Tom