Merging r356039:

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r356039 | atanasyan | 2019-03-13 04:04:38 -0700 (Wed, 13 Mar 2019) | 11 lines

[MIPS][microMIPS] Fix PseudoMTLOHI_MM matching and expansion

On micromips MipsMTLOHI is always matched to PseudoMTLOHI_DSP regardless
of +dsp argument. This patch checks is HasDSP predicate is present for
PseudoMTLOHI_DSP so PseudoMTLOHI_MM can be matched when appropriate.

Add expansion of PseudoMTLOHI_MM instruction into a mtlo/mthi pair.

Patch by Mirko Brkusanin.

Differential Revision: http://reviews.llvm.org/D59203
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llvm-svn: 358941