staging: unisys: visornic: remove useless memset

alloc_etherdev() calls alloc_netdev_mqs(), which
already uses kzalloc/vzalloc.

This clears a sparse warning :
drivers/staging/unisys/visornic/visornic_main.c:1366:15: warning: memset with byte count of 1460112
Signed-off-by: Hugo Camboulive <hugo.camboulive@gmail.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/visornic/visornic_main.c

@@ -1364,7 +1364,6 @@ devdata_initialize(struct visornic_devdata *devdata, struct visor_device *dev)
 {
 	if (!devdata)
 		return NULL;
-	memset(devdata, '\0', sizeof(struct visornic_devdata));
 	devdata->dev = dev;
 	devdata->incarnation_id = get_jiffies_64();
 	return devdata;