[llvm] r199287 - Only mark functions as micromips.

[Rafael Espíndola]

> I strongly suggest not doing something different for LLVM.  This stuff
> is hairy enough as it is without having two different interpretations
> of the same assembly.

Thank you so much for the explanation! Given it I agree that MC should
implement the same rules as gas. I reported pr18487 with the
information you provided.

I implemented ".set micromips" out of despair of repeatedly insisting
that mips should implement their MC layer and having they trying over
and over to "just use llc -filetype=obj". Having said that, my only
interest in mips is keeping MC sane. Before r199181 (and before
r192035) they were just marking functions in
MipsAsmPrinter::EmitFunctionEntryLabel, so I am pretty sure the
current state handles as many cases as before, but using the correct
MC interface.

Cheers,
Rafael