kobject: make kset_get_ownership() 'static'

kset_get_ownership() is only used in lib/kobject.c, so make it 'static'.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>