USB-SIS: Deletion of an unnecessary check before the function call "usb_put_dev"

The usb_put_dev() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/sisusbvga/sisusb.c

@@ -2472,7 +2472,6 @@ sisusb_delete(struct kref *kref)
 	if (!sisusb)
 		return;
 
-	if (sisusb->sisusb_dev)
 	usb_put_dev(sisusb->sisusb_dev);
 
 	sisusb->sisusb_dev = NULL;