hummingboard: Convert to generic board

Enable CONFIG_SYS_GENERIC_BOARD, so that we get rid of the following warning on
boot:

"Warning: Your board does not use generic board. Please read
doc/README.generic-board and take action. Boards not
upgraded by the late 2014 may break or be removed."

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

include/configs/hummingboard.h

@@ -27,6 +27,8 @@
 #define CONFIG_INITRD_TAG
 #define CONFIG_REVISION_TAG
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 /* Size of malloc() pool */
 #define CONFIG_SYS_MALLOC_LEN		(2 * SZ_1M)