Move DecodedInstruction into MIR.

Change-Id: I188dc7fef4f4033361c78daf2015b869242191c6
diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 72c46cc..9f15cd4 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -49,7 +49,7 @@
 
     uint64_t df_attributes = GetDataFlowAttributes(mir);
 
-    DecodedInstruction *d_insn = &mir->dalvikInsn;
+    MIR::DecodedInstruction* d_insn = &mir->dalvikInsn;
 
     if (!(df_attributes & DF_HAS_DEFS)) continue;