mei: bus: don't enable events implicitly in device enable

Do not enable events implicitly in mei_cl_enable_device, it should be
done explicitly using mei_cl_register_event_cb so the events
are enabled only when needed.
The NFC drivers has been already using it that way so no need for
further changes just remove the code from mei_cl_enable_device.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>