Bluetooth: btusb: Provide hardware error handler for Intel devices

The Intel Bluetooth controllers can provide an additional exception
info string when a hardware error event occurs. The core will now
call hdev->hw_error to let the driver read out this information.

This change will cause a reset of the hardware to bring it back
into functional state and then read the Intel exception info
string and print it along with the error information.

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