Remove VISIBILITY_HIDDEN from class/struct found inside anonymous namespaces.

Chris claims we should never have visibility_hidden inside any .cpp file but
that's still not true even after this commit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85042 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/LowerSubregs.cpp

@@ -30,8 +30,7 @@
 using namespace llvm;
 
 namespace {
-  struct VISIBILITY_HIDDEN LowerSubregsInstructionPass
-   : public MachineFunctionPass {
+  struct LowerSubregsInstructionPass : public MachineFunctionPass {
     static char ID; // Pass identification, replacement for typeid
     LowerSubregsInstructionPass() : MachineFunctionPass(&ID) {}