ppc4xx: Fix compilation problem of kilauea/haleakala nand booting target

Use correct link to nand_ecc now located in drivers/mtd/nand/ for the
platforms mentioned above.

Signed-off-by: Stefan Roese <sr@denx.de>

nand_spl/board/amcc/kilauea/Makefile

@@ -90,7 +90,7 @@ $(obj)nand_boot.c:
 # from drivers/nand directory
 $(obj)nand_ecc.c:
 	@rm -f $(obj)nand_ecc.c
-	ln -s $(SRCTREE)/drivers/nand/nand_ecc.c $(obj)nand_ecc.c
+	ln -s $(SRCTREE)/drivers/mtd/nand/nand_ecc.c $(obj)nand_ecc.c
 
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