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/Scheduler.h b/llvm/tools/llvm-mca/Scheduler.h
index f3b9a36..25bc87e 100644
--- a/llvm/tools/llvm-mca/Scheduler.h
+++ b/llvm/tools/llvm-mca/Scheduler.h
@@ -46,7 +46,7 @@
   RS_RESERVED
 };
 
-/// \brief A descriptor for processor resources.
+/// A descriptor for processor resources.
 ///
 /// Each object of class ResourceState is associated to a specific processor
 /// resource. There is an instance of this class for every processor resource
@@ -250,7 +250,7 @@
 #endif
 };
 
-/// \brief A resource unit identifier.
+/// A resource unit identifier.
 ///
 /// This is used to identify a specific processor resource unit using a pair
 /// of indices where the 'first' index is a processor resource mask, and the