Fix CFI fixups for long branches on MIPS.

Change-Id: Ibc078e6dc5d7ef423c6a3db855f19f1426e0ea5a
diff --git a/compiler/utils/assembler.h b/compiler/utils/assembler.h
index 4ea85a2..f70fe04 100644
--- a/compiler/utils/assembler.h
+++ b/compiler/utils/assembler.h
@@ -306,8 +306,10 @@
   // Override the last delayed PC. The new PC can be out of order.
   void OverrideDelayedPC(size_t pc) {
     DCHECK(delay_emitting_advance_pc_);
-    DCHECK(!delayed_advance_pcs_.empty());
-    delayed_advance_pcs_.back().pc = pc;
+    if (enabled_) {
+      DCHECK(!delayed_advance_pcs_.empty());
+      delayed_advance_pcs_.back().pc = pc;
+    }
   }
 
   // Return the number of delayed advance PC entries.