[ARM] add support for Cortex-R4/R4F

Adds ARM Cortex-R4 and R4F support and tests in Clang. Though Cortex-R4
support was present, the support for hwdiv in thumb-mode was not defined
or tested properly. This has also been added.

llvm-svn: 234488
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 7b661a7..f0fc574 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -5606,7 +5606,7 @@
     .Cases("arm1156t2-s",  "arm1156t2f-s", "v6t2")
     .Cases("cortex-a5", "cortex-a7", "cortex-a8", "v7")
     .Cases("cortex-a9", "cortex-a12", "cortex-a15", "cortex-a17", "krait", "v7")
-    .Cases("cortex-r4", "cortex-r5", "cortex-r7", "v7r")
+    .Cases("cortex-r4", "cortex-r4f", "cortex-r5", "cortex-r7", "v7r")
     .Cases("sc000", "cortex-m0", "cortex-m0plus", "cortex-m1", "v6m")
     .Cases("sc300", "cortex-m3", "v7m")
     .Cases("cortex-m4", "cortex-m7", "v7em")