[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/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 02641fb..9864d19 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -135,7 +135,7 @@
     .Cases("sc000", "cortex-m0", "cortex-m0plus", "cortex-m1", "armv6m")
     .Cases("cortex-a5", "cortex-a7", "cortex-a8", "armv7")
     .Cases("cortex-a9", "cortex-a12", "cortex-a15", "cortex-a17", "krait", "armv7")
-    .Cases("cortex-r4", "cortex-r5", "cortex-r7", "armv7r")
+    .Cases("cortex-r4", "cortex-r4f", "cortex-r5", "cortex-r7", "armv7r")
     .Cases("sc300", "cortex-m3", "armv7m")
     .Cases("cortex-m4", "cortex-m7", "armv7em")
     .Case("swift", "armv7s")