[llvm][ARM] Missing switch statement handles

PR llvm#115153 added enums which needed to be handled in
a switch statement. This trips up buildbot.

Change-Id: Ic361cffb51a0924a77adc573fe653a30fe017a42

Author: nasherm

llvm/lib/Target/ARM/ARMSubtarget.cpp

@@ -292,7 +292,9 @@ void ARMSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
   case CortexR5:
   case CortexR7:
   case CortexM3:
+  case CortexM55:
   case CortexM7:
+  case CortexM85:
   case CortexR52:
   case CortexR52plus:
   case CortexX1: