MIR Serialization: move the MIR printer out of the MIR printing pass.

This commit decouples the MIR printer and the MIR printing pass so
that it will be possible to move the MIR printer into a separate 
machine IR library later on.

Reviewers: Duncan P. N. Exon Smith
llvm-svn: 239788
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index 8ead486..a992c5e 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -73,6 +73,7 @@
   MachineSink.cpp
   MachineTraceMetrics.cpp
   MachineVerifier.cpp
+  MIRPrinter.cpp
   MIRPrintingPass.cpp
   OcamlGC.cpp
   OptimizePHIs.cpp