mips: Add smarter delay slot handling to emitter.
Merge pull request #7101 from unknownbrackets/mips-emitter

Add delay slot handling to the mips emitter
MIPS: Add MipsAsm file.
MIPS: Fix delay slots. Use NOPs for now.
Can probably use the Save/Restore downcounts.
MIPS: Set -march to mips32r2 for 32-bit MIPS.
It was using mips2 on debian, -march=native gives mips1.
Loongson, latest Ingenics and any other MIPS that has a hope of running is mips32r2 ISA.
MIPS: Fix a few issues. Save regs.
MIPS: Remove NOPs for delay slots (now automatic)