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/cpu/i386/serial.c b/cpu/i386/serial.c
index 8b5f8fa..e7025a3 100644
--- a/cpu/i386/serial.c
+++ b/cpu/i386/serial.c
@@ -26,6 +26,9 @@
 /*------------------------------------------------------------------------------+ */
 
 /*
+ * 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
  * copyrights to use it in any way he or she deems fit, including
diff --git a/cpu/ixp/npe/miiphy.c b/cpu/ixp/npe/miiphy.c
index 20fee2d..b208c51 100644
--- a/cpu/ixp/npe/miiphy.c
+++ b/cpu/ixp/npe/miiphy.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
diff --git a/cpu/ppc4xx/4xx_pci.c b/cpu/ppc4xx/4xx_pci.c
index 4b5d636..5d7d59c 100644
--- a/cpu/ppc4xx/4xx_pci.c
+++ b/cpu/ppc4xx/4xx_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
diff --git a/cpu/ppc4xx/4xx_uart.c b/cpu/ppc4xx/4xx_uart.c
index c106ac2..0780624 100644
--- a/cpu/ppc4xx/4xx_uart.c
+++ b/cpu/ppc4xx/4xx_uart.c
@@ -22,6 +22,9 @@
  */
 
 /*
+ * 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
  * copyrights to use it in any way he or she deems fit, including
diff --git a/cpu/ppc4xx/miiphy.c b/cpu/ppc4xx/miiphy.c
index 01710e7..6a92bf8 100644
--- a/cpu/ppc4xx/miiphy.c
+++ b/cpu/ppc4xx/miiphy.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
diff --git a/cpu/ppc4xx/start.S b/cpu/ppc4xx/start.S
index 60756c3..f967d84 100644
--- a/cpu/ppc4xx/start.S
+++ b/cpu/ppc4xx/start.S
@@ -25,6 +25,8 @@
  * MA 02111-1307 USA
  */
 /*------------------------------------------------------------------------------+
+ *   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