PATCH. Fix some ARM MLA instructions is not to be single used.

[Tim Northover]

Hi Yin,

> In ARM .td file, some MLA instructions has been marked to be single used.
> However, Some other MLA like instructions are not marked to be single used. The patch
> will Mark the rest of MLA like instruction definitions to be single used.

I can't find any record of "mul_su" already in the source, and in fact
this patch fails to compile for me because of that.

More generally, what can you tell us about why this is better? Take a
look at Evan's commit message where he introduced "fmul_su" (r120960).
There was quite a bit of extra infrastructure introduced there, as
well as simply a "single-use fmul" patten. Why isn't that needed to
exploit this change?

What example code does this make go faster for you? Have you tested it
on non-Qualcomm designs? What Qualcomm designs have you tested it on?

Finally, tests would be a good idea.

Cheers.

Tim.