[POWERPC] bootwrapper: no-gzip fixes

Commit a9903811bf8d130a26004f9cb27b66513a267908 missed two uses of the
the .gz suffix in the wrapper script and didn't clean the additonal
possibly cached files.

Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index be001d9..928b88a 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -170,5 +170,11 @@
 install: $(CONFIGURE) $(image-y)
 	sh -x $(srctree)/$(src)/install.sh "$(KERNELRELEASE)" vmlinux System.map "$(INSTALL_PATH)" $<
 
-clean-files += $(addprefix $(objtree)/, vmlinux.strip.gz vmlinux.bin.gz)
+# anything not in $(targets)
 clean-files += $(image-) $(initrd-) zImage zImage.initrd
+
+# clean up files cached by wrapper
+clean-kernel := vmlinux.strip vmlinux.bin
+clean-kernel += $(addsuffix .gz,$(clean-kernel))
+# If not absolute clean-files are relative to $(obj).
+clean-files += $(addprefix $(objtree)/, $(clean-kernel))