platform/chrome: fix kernel-doc warning for suspend_timeout_ms

Fix the following kernel-doc warning:

$ ./scripts/kernel-doc -none include/linux/platform_data/cros_ec_proto.h
include/linux/platform_data/cros_ec_proto.h:187: warning: Function
parameter or member 'suspend_timeout_ms' not described in 'cros_ec_device'

Cc: Evan Green <evgreen@chromium.org>
Fixes: e8bf17d5 ("platform/chrome: cros_ec: Expose suspend_timeout_ms in debugfs")
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20230111055728.708990-3-tzungbi@kernel.org

include/linux/platform_data/cros_ec_proto.h

@@ -131,6 +131,11 @@ struct cros_ec_command {
  * @event_data: Raw payload transferred with the MKBP event.
  * @event_size: Size in bytes of the event data.
  * @host_event_wake_mask: Mask of host events that cause wake from suspend.
+ * @suspend_timeout_ms: The timeout in milliseconds between when sleep event
+ *                      is received and when the EC will declare sleep
+ *                      transition failure if the sleep signal is not
+ *                      asserted.  See also struct
+ *                      ec_params_host_sleep_event_v1 in cros_ec_commands.h.
  * @last_event_time: exact time from the hard irq when we got notified of
  *     a new event.
  * @notifier_ready: The notifier_block to let the kernel re-query EC