net: tile: Remove unnecessary memset of netdev private data

The memory for private data is allocated using kzalloc/vzalloc in
alloc_netdev_mqs, thus there is no need to zero it again in the driver.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>