kbuild: pkg: clean up package files/dirs from the top Makefile

I am not a big fan of the $(objtree)/ hack for clean-files/clean-dirs.

These are created in the top of $(objtree), so let's clean them up
from the top Makefile.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/Makefile b/scripts/Makefile
index 16bcb80..c42891e1 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -36,4 +36,4 @@
 subdir-$(CONFIG_SECURITY_SELINUX) += selinux
 
 # Let clean descend into subdirs
-subdir-	+= basic dtc gdb kconfig mod package
+subdir-	+= basic dtc gdb kconfig mod