kconfig: ls1021a: add SUPPORT_SPL

Add SUPPORT_SPL feature for SD and NAND boot on
LS1021AQDS and LS1021ATWR.

Signed-off-by: Alison Wang <alison.wang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

arch/arm/Kconfig

@@ -730,10 +730,12 @@ config TARGET_LS2085A_SIMU
 config TARGET_LS1021AQDS
 	bool "Support ls1021aqds_nor"
 	select CPU_V7
+	select SUPPORT_SPL
 
 config TARGET_LS1021ATWR
 	bool "Support ls1021atwr_nor"
 	select CPU_V7
+	select SUPPORT_SPL
 
 config TARGET_BALLOON3
 	bool "Support balloon3"