Bluetooth: Add hci_reset_dev() for driver triggerd stack reset

Some Bluetooth drivers require to reset the upper stack. To avoid having
all drivers send HCI Hardware Error events, provide a generic function
to wrap the reset functionality.

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

diff --cc include/net/bluetooth/hci_core.h
Simple merge

diff --cc net/bluetooth/hci_core.c
Simple merge