fix method_missing register

logic is still wrong, even it is slightly less (at least loading the method name)

lib/slot_machine/macro/method_missing.rb

@@ -11,7 +11,7 @@ module SlotMachine
 
     def to_risc(compiler)
       builder = compiler.builder(compiler.source_name)
-      from = Risc::RegisterValue.new(@name , :Word)
+      from = compiler.load_object(Parfait.new_word(@name))
       to = Risc::RegisterValue.new(:r1 , :Word)
       builder.add_code Risc::Transfer.new(self , from , to)
       builder.add_code Risc::Syscall.new(self, :died )