Remove A6/A7 opcode maps. They can all be handled with a TB map, opcode of 0xa6/0xa7, and adding MRM_C0/MRM_E0 forms. Removes 376K from the disassembler tables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201641 91177308-0d34-0410-b5e6-96231b3b80d8