This patch implements jalx instruction for Mips architecture.This instruction executes a procedure call within the current 256 MB-aligned region and change the ISA Mode from MIPS32 to microMIPS32 or MIPS16e. Usage samples for assembler and dissasembler are provided as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202706 91177308-0d34-0410-b5e6-96231b3b80d8