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/BackendPrinter.h b/llvm/tools/llvm-mca/BackendPrinter.h
index d159a95..e367554 100644
--- a/llvm/tools/llvm-mca/BackendPrinter.h
+++ b/llvm/tools/llvm-mca/BackendPrinter.h
@@ -26,7 +26,7 @@
 
 namespace mca {
 
-/// \brief A printer class that knows how to collects statistics on the
+/// A printer class that knows how to collects statistics on the
 /// code analyzed by the llvm-mca tool.
 ///
 /// This class knows how to print out the analysis information collected