ppc4xx: Add SPL support

This patch adds SPL booting support (NOR flash) for the
PPC4xx platforms.

This SPL booting (Falcon mode) will be used by the upcoming
lcd4_lwmon5 board port (lwmon5 variant).

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/powerpc/cpu/ppc4xx/Makefile b/arch/powerpc/cpu/ppc4xx/Makefile
index 8da2f86..e301dc6 100644
--- a/arch/powerpc/cpu/ppc4xx/Makefile
+++ b/arch/powerpc/cpu/ppc4xx/Makefile
@@ -68,6 +68,10 @@
 COBJS	+= uic.o
 endif
 
+ifdef CONFIG_SPL_BUILD
+COBJS-y += spl_boot.o
+endif
+
 SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS) $(COBJS-y))
 START	:= $(addprefix $(obj),$(START))