Remove \brief commands from doxygen comments.

We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
diff --git a/llvm/lib/Target/PowerPC/PPCTargetObjectFile.h b/llvm/lib/Target/PowerPC/PPCTargetObjectFile.h
index c8b9b2e..417b8ed 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetObjectFile.h
+++ b/llvm/lib/Target/PowerPC/PPCTargetObjectFile.h
@@ -25,7 +25,7 @@
     MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
                                       const TargetMachine &TM) const override;
 
-    /// \brief Describe a TLS variable address within debug info.
+    /// Describe a TLS variable address within debug info.
     const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const override;
   };