[PowerPC] VSX register support for inline assembly

Summary:
The patch is to add the VSX register support for inline assembly. After this 
patch, we can use VSX register in inline assembly clobber list without error.

Reviewed By: jsji,  nemanjai

Differential Revision: https://reviews.llvm.org/D55192

llvm-svn: 348572
diff --git a/clang/lib/Basic/Targets/PPC.h b/clang/lib/Basic/Targets/PPC.h
index 97d04af..30f13c9 100644
--- a/clang/lib/Basic/Targets/PPC.h
+++ b/clang/lib/Basic/Targets/PPC.h
@@ -176,6 +176,8 @@
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override;
 
+  ArrayRef<TargetInfo::AddlRegName> getGCCAddlRegNames() const override;
+
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &Info) const override {
     switch (*Name) {