[mips] Add rsqrt, recip for MIPS

Add rsqrt.[ds], recip.[ds] for MIPS. Correct the microMIPS definitions for
architecture support and register usage.

Reviewers: vkalintiris, zoran.jovanoic

Differential Review: https://reviews.llvm.org/D24499


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282485 91177308-0d34-0410-b5e6-96231b3b80d8
61 files changed