ppc4xx: Fix NAND booting targets after 4xx linker script consolidation

Somehow I missed the NAND booting targets in the 4xx linker script
consolidation patchset. This patch fixes this issue.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/amcc/kilauea/config.mk b/board/amcc/kilauea/config.mk
index f5800eb..b3d3f22 100644
--- a/board/amcc/kilauea/config.mk
+++ b/board/amcc/kilauea/config.mk
@@ -30,3 +30,7 @@
 ifeq ($(debug),1)
 PLATFORM_CPPFLAGS += -DDEBUG
 endif
+
+ifdef CONFIG_NAND_U_BOOT
+LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot-nand.lds
+endif