can: etas_es58x: fix signedness of USB RX and TX pipes

USB pipes are meant to be unsigned int (c.f. [1]). However, fields
rx_pipe and tx_pipe of struct es58x_device are both signed
integers. Change the type of those two fields from int to unsigned
int.

[1] https://elixir.bootlin.com/linux/v5.18/source/include/linux/usb.h#L1571

Link: https://lore.kernel.org/all/20220611162037.1507-3-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.h

@@ -400,8 +400,8 @@ struct es58x_device {
 	const struct es58x_parameters *param;
 	const struct es58x_operators *ops;
 
-	int rx_pipe;
-	int tx_pipe;
+	unsigned int rx_pipe;
+	unsigned int tx_pipe;
 
 	struct usb_anchor rx_urbs;
 	struct usb_anchor tx_urbs_busy;