[AArch64] Add Tiny Code Model for AArch64

Adds a tiny code model to Clang along side rL340397.

Differential Revision: https://reviews.llvm.org/D49674

llvm-svn: 340398
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 826ac26..6da284e 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -368,6 +368,7 @@
 static Optional<llvm::CodeModel::Model>
 getCodeModel(const CodeGenOptions &CodeGenOpts) {
   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
+                           .Case("tiny", llvm::CodeModel::Tiny)
                            .Case("small", llvm::CodeModel::Small)
                            .Case("kernel", llvm::CodeModel::Kernel)
                            .Case("medium", llvm::CodeModel::Medium)