board/t208xrdb: Add support of 2-stage NAND/SPI/SD boot

Add support of 2-stage NAND/SPI/SD boot loader using SPL framework.
PBL initializes the internal CPC-SRAM and copy SPL(160K) to it,
SPL further initializes DDR using SPD and environment and copy
u-boot(768K) from SPI/SD/NAND to DDR, finally SPL transfers control
to u-boot.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/t208xrdb/Makefile b/board/freescale/t208xrdb/Makefile
index 092c9ff..9605f8b 100644
--- a/board/freescale/t208xrdb/Makefile
+++ b/board/freescale/t208xrdb/Makefile
@@ -4,10 +4,15 @@
 # SPDX-License-Identifier:      GPL-2.0+
 #
 
+ifdef CONFIG_SPL_BUILD
+obj-y += spl.o
+else
 obj-$(CONFIG_T2080RDB) += t208xrdb.o
 obj-$(CONFIG_T2080RDB) += eth_t208xrdb.o
 obj-$(CONFIG_T2080RDB) += cpld.o
 obj-$(CONFIG_PCI)      += pci.o
+endif
+
 obj-y   += ddr.o
 obj-y   += law.o
 obj-y   += tlb.o