acpiconf(8): tell users not to use -k
	Add language from jhb

Requested by:	jhb, jkim
Avoid the USB device disconnected and controller shutdown clutter on system
shutdown by putting the former under !rebooting and turning the latter into
debug messages.

Reviewed by:	hps
MFC after:	1 week
Sponsored by:	Bally Wulff Games & Entertainment GmbH