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/Hexagon/HexagonLoopIdiomRecognition.cpp b/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp
index f240a59..625e2e93 100644
--- a/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp
@@ -2295,7 +2295,7 @@
   return true;
 }
 
-// \brief Check if the instructions in Insts, together with their dependencies
+// Check if the instructions in Insts, together with their dependencies
 // cover the loop in the sense that the loop could be safely eliminated once
 // the instructions in Insts are removed.
 bool HexagonLoopIdiomRecognize::coverLoop(Loop *L,