[RegisterConfiguration] Streamline access to arch defaults, simplify Registers.

src/ppc/deoptimizer-ppc.cc

Index: src/ppc/deoptimizer-ppc.cc
diff --git a/src/ppc/deoptimizer-ppc.cc b/src/ppc/deoptimizer-ppc.cc
index ead877e1491dcce6665fd9b98ba681822a7ff60c..39102a1ef0b353dcbfa3f4c2052a132b0cf41cb6 100644
--- a/src/ppc/deoptimizer-ppc.cc
+++ b/src/ppc/deoptimizer-ppc.cc
@@ -124,8 +124,7 @@ void Deoptimizer::TableEntryGenerator::Generate() {
 
   // Save all double registers before messing with them.
   __ subi(sp, sp, Operand(kDoubleRegsSize));
-  const RegisterConfiguration* config =
-      RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT);
+  const RegisterConfiguration* config = RegisterConfiguration::Crankshaft();
   for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
     int code = config->GetAllocatableDoubleCode(i);
     const DoubleRegister dreg = DoubleRegister::from_code(code);