powerpc/T4QDS: add two stage boot of nand/sd

Add support of 2 stage NAND/SD boot loader using SPL framework.
PBL initialise the internal SRAM and copy SPL, this further
initialise DDR using SPD and environment and copy u-boot from
NAND/SD to DDR, finally SPL transfer control to u-boot.
NOR uses CS1 instead of CS2 when NAND boot, fix it.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/t4qds/Makefile b/board/freescale/t4qds/Makefile
index 2b1f7aa..4e8e5cb 100644
--- a/board/freescale/t4qds/Makefile
+++ b/board/freescale/t4qds/Makefile
@@ -4,10 +4,14 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+ifdef CONFIG_SPL_BUILD
+obj-y += spl.o
+else
 obj-$(CONFIG_T4240QDS) += t4240qds.o
 obj-$(CONFIG_T4240EMU) += t4240emu.o
-obj-y	+= ddr.o
 obj-$(CONFIG_T4240QDS)+= eth.o
 obj-$(CONFIG_PCI)	+= pci.o
+endif
+obj-y	+= ddr.o
 obj-y	+= law.o
 obj-y	+= tlb.o