- DCHECK(IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) is failed.
- I tried not to select instruction kMipsSeb in case of kMips32r1.

R=ivica.bogosavljevic@mips.com

Bug: v8:8006
Change-Id: If07450b1a35b4e9cb608344e137c032381da224d
Reviewed-on: https://chromium-review.googlesource.com/1160073
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Ivica Bogosavljevic <ibogosavljevic@wavecomp.com>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54931}