Remove special FP opcode maps and instead add enough MRM_XX formats to handle all the FP operations. This increases format by 1 bit, but decreases opcode map by 1 bit so the TSFlags size doesn't change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201649 91177308-0d34-0410-b5e6-96231b3b80d8