[X86] Add AES to KNL CPUs to match clang.

I believe this was lost from KNL when AES was pushed from Westmere to Skylake recently. KNL used to inherit from IVB.

llvm-svn: 345519

Author: topperc

llvm/lib/Target/X86/X86.td

@@ -826,6 +826,7 @@ def KNLFeatures : ProcessorFeatures<[], [
   FeatureLAHFSAHF,
   FeatureSlow3OpsLEA,
   FeatureSlowIncDec,
+  FeatureAES,
   FeatureRDRAND,
   FeatureF16C,
   FeatureFSGSBase,