Move fused cmp branch ccode to MIR::meta.

This a small refactoring towards removing the large
DecodedInstruction from the MIR class.

Change-Id: I10f9ed5eaac42511d864c71d20a8ff6360292cec
diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index ee9f28e..5c41520 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -259,7 +259,7 @@
             if ((ccode != kCondNv) &&
                 (mir->ssa_rep->defs[0] == mir_next->ssa_rep->uses[0]) &&
                 (GetSSAUseCount(mir->ssa_rep->defs[0]) == 1)) {
-              mir_next->dalvikInsn.arg[0] = ccode;
+              mir_next->meta.ccode = ccode;
               switch (opcode) {
                 case Instruction::CMPL_FLOAT:
                   mir_next->dalvikInsn.opcode =