Bluetooth: Move idle_timeout and sniff_{min,max}_interval to hci_core.c

Move the debugfs configuration directly into hci_core.c and only expose
it when the controller actually support BR/EDR sniff power saving mode.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>