usbdebug: Use __SIMPLE_DEVICE__ on early enable

With USBDEBUG selected, the file is built for both romstage and
ramstage. For the ramstage build, we need to explicitly use the
simple PCI config operations without devicetree.

Change-Id: I2de8d9c77bb458ba797c3aac9e2cd0d653e06684
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3437
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/src/southbridge/amd/agesa/hudson/enable_usbdebug.c b/src/southbridge/amd/agesa/hudson/enable_usbdebug.c
index 128885a..147056d 100644
--- a/src/southbridge/amd/agesa/hudson/enable_usbdebug.c
+++ b/src/southbridge/amd/agesa/hudson/enable_usbdebug.c
@@ -16,6 +16,10 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
+
+// Use simple device model for this file even in ramstage
+#define __SIMPLE_DEVICE__
+
 #include <stdint.h>
 #include <arch/io.h>
 #include <usbdebug.h>