usb: misc: uss720: fix uninitialized variable rlen

Smatch reports the following error: uninitialized symbol 'rlen'

drivers/usb/misc/uss720.c:514 parport_uss720_epp_write_data() error
drivers/usb/misc/uss720.c:575 parport_uss720_ecp_write_data() error
drivers/usb/misc/uss720.c:593 parport_uss720_ecp_read_data() error
drivers/usb/misc/uss720.c:626 parport_uss720_write_compat() error

The root cause is, the failure of usb_bulk_msg leads to the
uninitialized variable rlen in printk function.

Fix this by initializing rlen with zero.
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Link: https://lore.kernel.org/r/20220903100004.2874741-1-dzm91@hust.edu.cnSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/uss720.c

@@ -502,7 +502,7 @@ static size_t parport_uss720_epp_write_data(struct parport *pp, const void *buf,
 #else
 	struct parport_uss720_private *priv = pp->private_data;
 	struct usb_device *usbdev = priv->usbdev;
-	int rlen;
+	int rlen = 0;
 	int i;
 
 	if (!usbdev)
@@ -563,7 +563,7 @@ static size_t parport_uss720_ecp_write_data(struct parport *pp, const void *buff
 {
 	struct parport_uss720_private *priv = pp->private_data;
 	struct usb_device *usbdev = priv->usbdev;
-	int rlen;
+	int rlen = 0;
 	int i;
 
 	if (!usbdev)
@@ -581,7 +581,7 @@ static size_t parport_uss720_ecp_read_data(struct parport *pp, void *buffer, siz
 {
 	struct parport_uss720_private *priv = pp->private_data;
 	struct usb_device *usbdev = priv->usbdev;
-	int rlen;
+	int rlen = 0;
 	int i;
 
 	if (!usbdev)
@@ -614,7 +614,7 @@ static size_t parport_uss720_write_compat(struct parport *pp, const void *buffer
 {
 	struct parport_uss720_private *priv = pp->private_data;
 	struct usb_device *usbdev = priv->usbdev;
-	int rlen;
+	int rlen = 0;
 	int i;
 
 	if (!usbdev)