Initialize SIInsertWaits::ExpInstrTypesSeen in the pass constructor.

This value may be used uninitialized in SIInsertWaits::insertWait.
Found with MemorySanitizer.

llvm-svn: 187869

llvm/lib/Target/R600/SIInsertWaits.cpp

@@ -98,7 +98,8 @@ public:
   SIInsertWaits(TargetMachine &tm) :
     MachineFunctionPass(ID),
     TII(0),
-    TRI(0) { }
+    TRI(0),
+    ExpInstrTypesSeen(0) { }
 
   virtual bool runOnMachineFunction(MachineFunction &MF);