buildroot

Makefile: fixup make distclean after kconfig build in BUILD_DIR

We don't actually need to explicitly clean the kconfig stuff, as distclean
already removes the entire BUILD_DIR, but fix up the packag/config makefile
to do the right thing if make clean/distclean is called manually for
completeness.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>