platform/chrome: cros_ec_proto: return -EAGAIN when retries timed out

While EC_COMMS_STATUS_PROCESSING flag is still on after it tries
EC_COMMAND_RETRIES times for sending EC_CMD_GET_COMMS_STATUS,
cros_ec_wait_until_complete() doesn't return an error code.

Return -EAGAIN in the case instead.
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20220718050914.2267370-9-tzungbi@kernel.org

drivers/platform/chrome/cros_ec_proto.c

@@ -167,6 +167,9 @@ static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t *
 			return ret;
 	}
 
+	if (i >= EC_COMMAND_RETRIES)
+		ret = -EAGAIN;
+
 	return ret;
 }