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/tools/llvm-mca/InstrBuilder.h b/llvm/tools/llvm-mca/InstrBuilder.h
index a3b7001..30af1bf 100644
--- a/llvm/tools/llvm-mca/InstrBuilder.h
+++ b/llvm/tools/llvm-mca/InstrBuilder.h
@@ -24,7 +24,7 @@
 
 class DispatchUnit;
 
-/// \brief A builder class that knows how to construct Instruction objects.
+/// A builder class that knows how to construct Instruction objects.
 ///
 /// Every llvm-mca Instruction is described by an object of class InstrDesc.
 /// An InstrDesc describes which registers are read/written by the instruction,