kconfig: rename loose_nonint_oldconfig => oldnoconfig

Rename target to something that fall more in line
with the other kconfig targets.

oldnoconfig shall read as:

- read the old configuration and set all new options to no

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>