Teach the Neon intrinsic generator to widen half-precision float types.

This isn't currently used for anything but I ran into it when experimenting
with some changes, and it might be useful in the future.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121911 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/NeonEmitter.cpp

@@ -73,6 +73,8 @@ static char Widen(const char t) {
       return 'i';
     case 'i':
       return 'l';
+    case 'h':
+      return 'f';
     default: throw "unhandled type in widen!";
   }
   return '\0';