Dual-license IBM code contributions

It was brought to our attention that U-Boot contains code derived from the
IBM OpenBIOS source code originally provided with some of the older PowerPC
4xx development boards.  As a result, the original license of this code has
been carried in the various files for a number of years in the U-Boot project.

IBM is dual-licensing the IBM code contributions already present in U-Boot
under either the terms of the GNU General Public License version 2, or the
original code license already present.

Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
diff --git a/board/mpl/common/pci.c b/board/mpl/common/pci.c
index bfd6428..e0ba620 100644
--- a/board/mpl/common/pci.c
+++ b/board/mpl/common/pci.c
@@ -1,4 +1,6 @@
 /*-----------------------------------------------------------------------------+
+|       This source code is dual-licensed.  You may use it under the terms of
+|       the GNU General Public License version 2, or under the license below.
 |
 |       This source code has been made available to you by IBM on an AS-IS
 |       basis.  Anyone receiving this source is licensed under IBM