R600/SI: fix warning about overloaded virtual

Signed-off-by: Christian König <christian.koenig@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176343 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/R600/AMDGPUStructurizeCFG.cpp b/lib/Target/R600/AMDGPUStructurizeCFG.cpp
index 26f842e..b723433 100644
--- a/lib/Target/R600/AMDGPUStructurizeCFG.cpp
+++ b/lib/Target/R600/AMDGPUStructurizeCFG.cpp
@@ -243,6 +243,7 @@
     initializeRegionInfoPass(*PassRegistry::getPassRegistry());
   }
 
+  using Pass::doInitialization;
   virtual bool doInitialization(Region *R, RGPassManager &RGM);
 
   virtual bool runOnRegion(Region *R, RGPassManager &RGM);