Adds support for the Cortex-A17 to the ARM backend

Patch by Matthew Wahab.

llvm-svn: 219606
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index 8c85ad7..12899f9 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -42,7 +42,7 @@
 protected:
   enum ARMProcFamilyEnum {
     Others, CortexA5, CortexA7, CortexA8, CortexA9, CortexA12, CortexA15,
-    CortexR5, Swift, CortexA53, CortexA57, Krait
+    CortexA17, CortexR5, Swift, CortexA53, CortexA57, Krait, 
   };
   enum ARMProcClassEnum {
     None, AClass, RClass, MClass