Makefile: remove MLO.byteswap on clobber

On clobber, do a cleanup even for SPL build else, we'd have
MLO.byteswap remaining for certain platforms like am33xx SPL builds

Signed-off-by: Nishanth Menon <nm@ti.com>

Makefile

@@ -869,7 +869,7 @@ clobber:	tidy
 	@rm -f $(obj)nand_spl/{u-boot-nand_spl.lds,u-boot-spl,u-boot-spl.map}
 	@rm -f $(obj)spl/{u-boot-spl,u-boot-spl.bin,u-boot-spl.map}
 	@rm -f $(obj)spl/{u-boot-spl.lds,u-boot.lst}
-	@rm -f $(obj)MLO
+	@rm -f $(obj)MLO MLO.byteswap
 	@rm -f $(obj)SPL
 	@rm -f $(obj)tools/xway-swap-bytes
 	@rm -f $(obj)arch/powerpc/cpu/mpc824x/bedbug_603e.c