can: etas_es58x: replace es58x_device::rx_max_packet_size by usb_maxpacket()

The field rx_max_packet_size of struct es58x_device in nothing else
than usb_endpoint_descriptor::wMaxPacketSize and can be easily
retrieved using usb_maxpacket(). Also, rx_max_packet_size being used a
single time, there is no merit to cache it locally.

Remove es58x_device::rx_max_packet_size and rely on usb_maxpacket()
instead.

Link: https://lore.kernel.org/all/20220611162037.1507-2-mailhol.vincent@wanadoo.frSigned-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/etas_es58x/es58x_core.c

@@ -1707,7 +1707,7 @@ static int es58x_alloc_rx_urbs(struct es58x_device *es58x_dev)
 {
 	const struct device *dev = es58x_dev->dev;
 	const struct es58x_parameters *param = es58x_dev->param;
-	size_t rx_buf_len = es58x_dev->rx_max_packet_size;
+	u16 rx_buf_len = usb_maxpacket(es58x_dev->udev, es58x_dev->rx_pipe);
 	struct urb *urb;
 	u8 *buf;
 	int i;
@@ -1739,7 +1739,7 @@ static int es58x_alloc_rx_urbs(struct es58x_device *es58x_dev)
 		dev_err(dev, "%s: Could not setup any rx URBs\n", __func__);
 		return ret;
 	}
-	dev_dbg(dev, "%s: Allocated %d rx URBs each of size %zu\n",
+	dev_dbg(dev, "%s: Allocated %d rx URBs each of size %u\n",
 		__func__, i, rx_buf_len);
 
 	return ret;
@@ -2223,7 +2223,6 @@ static struct es58x_device *es58x_init_es58x_dev(struct usb_interface *intf,
 					     ep_in->bEndpointAddress);
 	es58x_dev->tx_pipe = usb_sndbulkpipe(es58x_dev->udev,
 					     ep_out->bEndpointAddress);
-	es58x_dev->rx_max_packet_size = le16_to_cpu(ep_in->wMaxPacketSize);
 
 	return es58x_dev;
 }

drivers/net/can/usb/etas_es58x/es58x_core.h

@@ -380,7 +380,6 @@ struct es58x_operators {
  * @timestamps: a temporary buffer to store the time stamps before
  *	feeding them to es58x_can_get_echo_skb(). Can only be used
  *	in RX branches.
- * @rx_max_packet_size: Maximum length of bulk-in URB.
  * @num_can_ch: Number of CAN channel (i.e. number of elements of @netdev).
  * @opened_channel_cnt: number of channels opened. Free of race
  *	conditions because its two users (net_device_ops:ndo_open()
@@ -414,7 +413,6 @@ struct es58x_device {
 
 	u64 timestamps[ES58X_ECHO_BULK_MAX];
 
-	u16 rx_max_packet_size;
 	u8 num_can_ch;
 	u8 opened_channel_cnt;