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/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
index 7a8d422..78b94a2 100644
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -470,7 +470,7 @@
   }
 }
 
-/// \brief Return the cost of spilling clearing out PhysReg and aliases so it is
+/// Return the cost of spilling clearing out PhysReg and aliases so it is
 /// free for allocation. Returns 0 when PhysReg is free or disabled with all
 /// aliases disabled - it can be allocated directly.
 /// \returns spillImpossible when PhysReg or an alias can't be spilled.
@@ -519,7 +519,7 @@
   return Cost;
 }
 
-/// \brief This method updates local state so that we know that PhysReg is the
+/// This method updates local state so that we know that PhysReg is the
 /// proper container for VirtReg now.  The physical register must not be used
 /// for anything else when this is called.
 void RegAllocFast::assignVirtToPhysReg(LiveReg &LR, MCPhysReg PhysReg) {