RFC on writel and writel_relaxed

[David Laight]

From: Oliver
> Sent: 22 March 2018 05:24
...
> > No less painful was doing a byteswapping write to normal memory.
> 
> What was the problem? The reverse indexed load/store instructions are
> a little awkward to use, but they work...

Finding something that would generate the right instruction without any
barriers.
ISTR writing my own asm pattern.

	David