main.c has initcall_level_names[] for parse_args to print in debug messages,
add comments to keep them in sync with initcalls defined in init.h.

Also add "loadable" into comment re not using *_initcall macros in
modules, to disambiguate from kernel/params.c and other builtins.
Signed-off-by: NJim Cromie <jim.cromie@gmail.com>
Acked-by: NBorislav Petkov <borislav.petkov@amd.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>