board/t104xrdb: Add support of NAND, SD, SPI boot for T104xRDB

Add support of 2 stage NAND, SD, SPI boot loader using SPL framework.
here, PBL initialise the internal SRAM and copy SPL(160KB). This further
initialise DDR using SPD and environment and copy u-boot(768 KB) from NAND to DDR.
Finally SPL transer control to u-boot.

Initialise/create followings required for SPL framework
      - Add spl.c which defines board_init_f, board_init_r
      - update tlb and ddr accordingly

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/t104xrdb/Makefile b/board/freescale/t104xrdb/Makefile
index 7e7bfb1..6cd304c 100644
--- a/board/freescale/t104xrdb/Makefile
+++ b/board/freescale/t104xrdb/Makefile
@@ -4,11 +4,14 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-
+ifdef CONFIG_SPL_BUILD
+obj-y += spl.o
+else
 obj-y	+= t104xrdb.o
 obj-y	+= cpld.o
-obj-y	+= ddr.o
 obj-y	+= eth.o
 obj-$(CONFIG_PCI)	+= pci.o
+endif
+obj-y	+= ddr.o
 obj-y	+= law.o
 obj-y	+= tlb.o