Makefile: Add another kwb build target used on Marvell Armada-XP (AXP)

This build target now includes the SPL binary as the bin_hdr into the
kwb image. Its used on the AXP port with the mainlined DDR training code.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Luka Perkov <luka.perkov@sartura.hr>

Makefile

@@ -856,12 +856,18 @@ MKIMAGEFLAGS_u-boot.img = -A $(ARCH) -T firmware -C none -O u-boot \
 MKIMAGEFLAGS_u-boot.kwb = -n $(srctree)/$(CONFIG_SYS_KWD_CONFIG:"%"=%) \
 	-T kwbimage -a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE)
 
+MKIMAGEFLAGS_u-boot-spl.kwb = -n $(srctree)/$(CONFIG_SYS_KWD_CONFIG:"%"=%) \
+	-T kwbimage -a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE)
+
 MKIMAGEFLAGS_u-boot.pbl = -n $(srctree)/$(CONFIG_SYS_FSL_PBL_RCW:"%"=%) \
 		-R $(srctree)/$(CONFIG_SYS_FSL_PBL_PBI:"%"=%) -T pblimage
 
 u-boot.img u-boot.kwb u-boot.pbl: u-boot.bin FORCE
 	$(call if_changed,mkimage)
 
+u-boot-spl.kwb: u-boot.img spl/u-boot-spl.bin FORCE
+	$(call if_changed,mkimage)
+
 MKIMAGEFLAGS_u-boot-dtb.img = $(MKIMAGEFLAGS_u-boot.img)
 
 u-boot-dtb.img: u-boot-dtb.bin FORCE