[ARM]: add missing switch case for cortex-r52

Adds a missing switch case for handling cortex-r52
in init-subtarget-features.

llvm-svn: 283551
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index a90b495..f39e792 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -244,6 +244,7 @@
   case CortexR7:
   case CortexM3:
   case ExynosM1:
+  case CortexR52:
     break;
   case Krait:
     PreISelOperandLatencyAdjustment = 1;