can: ucan: use strscpy() to instead of strncpy()

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.
Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Yang Yang <yang.yang29@zte.com>
Link: https://lore.kernel.org/all/202212070909095189693@zte.com.cnSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/ucan.c

@@ -1534,9 +1534,8 @@ static int ucan_probe(struct usb_interface *intf,
 				     sizeof(union ucan_ctl_payload));
 	if (ret > 0) {
 		/* copy string while ensuring zero termination */
-		strncpy(firmware_str, up->ctl_msg_buffer->raw,
-			sizeof(union ucan_ctl_payload));
-		firmware_str[sizeof(union ucan_ctl_payload)] = '\0';
+		strscpy(firmware_str, up->ctl_msg_buffer->raw,
+			sizeof(union ucan_ctl_payload) + 1);
 	} else {
 		strcpy(firmware_str, "unknown");
 	}