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/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp
index 023baaa..26d4aaa 100644
--- a/llvm/lib/Target/ARM/ARMFastISel.cpp
+++ b/llvm/lib/Target/ARM/ARMFastISel.cpp
@@ -2913,7 +2913,7 @@
   { { ARM::UXTB,  ARM::t2UXTB  },   0, 1, MVT::i8  }
 };
 
-/// \brief The specified machine instr operand is a vreg, and that
+/// The specified machine instr operand is a vreg, and that
 /// vreg is being provided by the specified load instruction.  If possible,
 /// try to fold the load as an operand to the instruction, returning true if
 /// successful.