usb: misc: sisusbvga: fix information leak to userland

Structure sisusb_info is copied to userland with "sisusb_reserved" field
uninitialized.  It leads to leaking of contents of kernel stack memory.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/sisusbvga/sisusb.c

@@ -3008,6 +3008,7 @@ sisusb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 #else
 			x.sisusb_conactive  = 0;
 #endif
+			memset(x.sisusb_reserved, 0, sizeof(x.sisusb_reserved));
 
 			if (copy_to_user((void __user *)arg, &x, sizeof(x)))
 				retval = -EFAULT;