[Mips][msa] Add support for half

Add support for half (a.k.a. __fp16) in builtin descriptions. 
The second argument to BUILTIN() now accepts 'h' to represent half.

Patch by Daniel Sanders


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188464 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index f38a248..29ddb37 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -7552,6 +7552,11 @@
            "Bad modifiers used with 'v'!");
     Type = Context.VoidTy;
     break;
+  case 'h':
+    assert(HowLong == 0 && !Signed && !Unsigned &&
+           "Bad modifiers used with 'f'!");
+    Type = Context.HalfTy;
+    break;
   case 'f':
     assert(HowLong == 0 && !Signed && !Unsigned &&
            "Bad modifiers used with 'f'!");