w1: w1_process() is not freezable kthread

w1_process() calls try_to_freeze(), but the thread doesn't mark itself
freezable through set_freezable(), so the try_to_freeze() call is useless.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>