imx: mx6slevk: Change to use generic board

Enable CONFIG_SYS_GENERIC_BOARD for imx6slevk to use generic board.

Signed-off-by: Ye.Li <B37916@freescale.com>
diff --git a/include/configs/mx6slevk.h b/include/configs/mx6slevk.h
index 3d05a64..194d7bd 100644
--- a/include/configs/mx6slevk.h
+++ b/include/configs/mx6slevk.h
@@ -26,6 +26,8 @@
 #define CONFIG_INITRD_TAG
 #define CONFIG_REVISION_TAG
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 /* Size of malloc() pool */
 #define CONFIG_SYS_MALLOC_LEN		(3 * SZ_1M)