PCI: fix VGA arbiter header file

Remove reference to vgaarb.c and replace it with a comment about the
arbiter itself.

Reported-by: Tiago Vignatti <tiago.vignatti@nokia.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index e81c64a..a1fa1da 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -1,5 +1,6 @@
 /*
- * vgaarb.c
+ * The VGA aribiter manages VGA space routing and VGA resource decode to
+ * allow multiple VGA devices to be used in a system in a safe way.
  *
  * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
  * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>