powerpc/freescale: Convert selected boards to generic board architecture

This patch converts the following boards to use generic board: MPC8536DS,
MPC8572DS, MPC8641HPCN, p1_p2_rdb_pc, corenet_ds, t4qds, B4860QDS. It has
been tested on NOR boot on MPC8536DS, MPC8572DS, P1021RDB, P4080DS,
P5020DS, P5040DS, P3041DS, T4240QDS, B4860QDS.

Signed-off-by: York Sun <yorksun@freescale.com>
CC: Ying Zhang <b40530@freescale.com>
CC: Prabhakar Kushwaha <prabhakar@freescale.com>
CC: Haijun.Zhang <Haijun.Zhang@freescale.com>
CC: Scott Wood <scottwood@freescale.com>
CC: Shaohui Xie <Shaohui.Xie@freescale.com>
diff --git a/include/configs/MPC8536DS.h b/include/configs/MPC8536DS.h
index f15e162..72f5fde 100644
--- a/include/configs/MPC8536DS.h
+++ b/include/configs/MPC8536DS.h
@@ -11,6 +11,8 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#define CONFIG_SYS_GENERIC_BOARD
+#define CONFIG_DISPLAY_BOARDINFO
 #include "../board/freescale/common/ics307_clk.h"
 
 #ifdef CONFIG_36BIT