Makefile: need to remove generated u-boot-nand_spl.lds

On MPC85xx based NAND_SPL builds we generate a u-boot-nand_spl.lds based
on output from preprocessor.  We where never removed it.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NScott Wood <scottwood@freescale.com>

Makefile

@@ -1078,7 +1078,7 @@ clean:
 	       $(obj)arch/blackfin/cpu/bootrom-asm-offsets.[chs]
 	@rm -f $(obj)include/bmp_logo.h
 	@rm -f $(obj)lib/asm-offsets.s
-	@rm -f $(obj)nand_spl/{u-boot.lds,u-boot-spl,u-boot-spl.map,System.map}
+	@rm -f $(obj)nand_spl/{u-boot.lds,u-boot-nand_spl.lds,u-boot-spl,u-boot-spl.map,System.map}
 	@rm -f $(obj)onenand_ipl/onenand-{ipl,ipl.bin,ipl.map}
 	@rm -f $(obj)mmc_spl/{u-boot.lds,u-boot-spl,u-boot-spl.map,u-boot-spl.bin,u-boot-mmc-spl.bin}
 	@rm -f $(ONENAND_BIN)