powerpc: ppc4xx: canyonlands: Move to generic board

Switch to generic board so that this board will not be broken/removed.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/canyonlands.h b/include/configs/canyonlands.h
index ed790cc..7a1499d 100644
--- a/include/configs/canyonlands.h
+++ b/include/configs/canyonlands.h
@@ -13,6 +13,8 @@
 
 #include <linux/kconfig.h>
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 /*-----------------------------------------------------------------------
  * High Level Configuration Options
  *----------------------------------------------------------------------*/