[InlineAsm] Add missing constraint A to getMemConstraintName

[Jim]

Summary

Constraint A was added from https://reviews.llvm.org/D54296.

Clang will crash with option -mllvm --debug due to lack of constraint name for constraint A.

[Jim]

This patch only add missing case in getMemConstraintName.
Could someone help to take a review. Thanks.

llvm/include/llvm/IR/InlineAsm.h

static StringRef getMemConstraintName(unsigned Constraint) {
     case InlineAsm::Constraint_i:
       return "i";
     case InlineAsm::Constraint_m:
       return "m";
     case InlineAsm::Constraint_o:
       return "o";
     case InlineAsm::Constraint_v:
       return "v";
+    case InlineAsm::Constraint_A:
+      return "A";
     case InlineAsm::Constraint_Q:
       return "Q";
     case InlineAsm::Constraint_R:
       return "R";
     case InlineAsm::Constraint_S:
       return "S";
     case InlineAsm::Constraint_T:
       return "T";