platform/chrome: cros_ec_rpmsg: Document missing struct parameters

Kerneldoc expects all kernel structure member to be documented.

Fixes the following W=1 level warnings:

  cros_ec_rpmsg.c:49: warning: Function parameter or member 'ept' not described in 'cros_ec_rpmsg'
  cros_ec_rpmsg.c:49: warning: Function parameter or member 'has_pending_host_event' not described in 'cros_ec_rpmsg'
  cros_ec_rpmsg.c:49: warning: Function parameter or member 'probe_done' not described in 'cros_ec_rpmsg'

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>

drivers/platform/chrome/cros_ec_rpmsg.c

@@ -38,6 +38,9 @@ struct cros_ec_rpmsg_response {
  * @rpdev:	rpmsg device we are connected to
  * @xfer_ack:	completion for host command transfer.
  * @host_event_work:	Work struct for pending host event.
+ * @ept: The rpmsg endpoint of this channel.
+ * @has_pending_host_event: Boolean used to check if there is a pending event.
+ * @probe_done: Flag to indicate that probe is done.
  */
 struct cros_ec_rpmsg {
 	struct rpmsg_device *rpdev;