[Patch, MIPS] Modify memset.S for mips32r6/mips64r6

[Joseph Myers]

On Mon, 22 Dec 2014, Steve Ellcey wrote:

> I considered changing the alignment code to only align on a 4 byte
> boundary for O32 mode, or ifdef'ing this test but it seemed cleaner to
> increase the minimum size of buffers that get handled via a simple byte
> copy loop for both r6 and earlier CPU's.

In that case, submit the change as a preparatory patch, with its own 
justification for being OK for existing CPUs (that it doesn't affect 
performance, or whatever), so that the r6 patch can avoid changing pre-r6 
code.

-- 
Joseph S. Myers
joseph@codesourcery.com