Add cmd_spl command

This adds a spl command to the u-boot.

Related config:
CONFIG_CMD_SPL
	activate/deactivate the command
CONFIG_CMD_SPL_NAND_OFS
	Offset in NAND to use

Signed-off-by: Simon Schwarz <simonschwarzcor@gmail.com>
Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Tom Rini <tom.rini@gmail.com>
CC: Wolfgang Denk <wd@denx.de>
diff --git a/common/Makefile b/common/Makefile
index 04faa0b..ed2fb45 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -162,6 +162,7 @@
 endif
 COBJS-$(CONFIG_CMD_XIMG) += cmd_ximg.o
 COBJS-$(CONFIG_YAFFS2) += cmd_yaffs2.o
+COBJS-$(CONFIG_CMD_SPL) += cmd_spl.o
 
 # others
 ifdef CONFIG_DDR_SPD