kbuild: pkg: rename scripts/package/Makefile to scripts/Makefile.package

scripts/package/Makefile does not use $(obj) or $(src) at all.
It actually generates files and directories in the top of $(objtree).
I do not see much sense in descending into scripts/package/.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/Makefile b/Makefile
index 69cb3ec..668e65c 100644
--- a/Makefile
+++ b/Makefile
@@ -1445,13 +1445,11 @@
 
 # Packaging of the kernel to various formats
 # ---------------------------------------------------------------------------
-package-dir	:= scripts/package
 
 %src-pkg: FORCE
-	$(Q)$(MAKE) $(build)=$(package-dir) $@
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
 %pkg: include/config/kernel.release FORCE
-	$(Q)$(MAKE) $(build)=$(package-dir) $@
-
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
 
 # Brief documentation of the typical targets used
 # ---------------------------------------------------------------------------
@@ -1523,7 +1521,7 @@
 	@echo '  or  "cd tools; make help"'
 	@echo  ''
 	@echo  'Kernel packaging:'
-	@$(MAKE) $(build)=$(package-dir) help
+	@$(MAKE) -f $(srctree)/scripts/Makefile.package help
 	@echo  ''
 	@echo  'Documentation targets:'
 	@$(MAKE) -f $(srctree)/Documentation/Makefile dochelp