[POWERPC] Fixed some missing files to be deleted when running make clean

Fixed some missing files to be deleted when running make clean
Signed-off-by: NMatthew McClintock <msm@freescale.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/boot/Makefile

@@ -75,7 +75,7 @@ $(obj)/zImage.lds $(obj)/zImage.coff.lds: $(obj)/%: $(srctree)/$(src)/%.S
 	@cp $< $@
 
 clean-files := $(zlib) $(zlibheader) $(zliblinuxheader) \
-		$(obj)/empty.c
+		empty.c zImage.coff.lds zImage.lds zImage.sandpoint
 
 quiet_cmd_bootcc = BOOTCC  $@
       cmd_bootcc = $(CROSS32CC) -Wp,-MD,$(depfile) $(BOOTCFLAGS) -c -o $@ $<