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/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 154736a..b6af11d 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -476,7 +476,7 @@
   }
 }
 
-/// \brief Write the fragment \p F to the output file.
+/// Write the fragment \p F to the output file.
 static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
                           const MCFragment &F) {
   MCObjectWriter *OW = Asm.getWriterPtr();