can: etas_es58x: use BITS_PER_TYPE() instead of manual calculation

The input to the GENMASK() macro was calculated by hand. Replaced it
with a dedicated macro: BITS_PER_TYPE() which does the exact same job.

Link: https://lore.kernel.org/all/20220212130737.3008-1-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_fd.c

@@ -69,7 +69,8 @@ static int es58x_fd_echo_msg(struct net_device *netdev,
 	int i, num_element;
 	u32 rcv_packet_idx;
 
-	const u32 mask = GENMASK(31, sizeof(echo_msg->packet_idx) * 8);
+	const u32 mask = GENMASK(BITS_PER_TYPE(mask) - 1,
+				 BITS_PER_TYPE(echo_msg->packet_idx));
 
 	num_element = es58x_msg_num_element(es58x_dev->dev,
 					    es58x_fd_urb_cmd->echo_msg,