net: tile: fix unused variable warning

'i' is unused in tile_net_dev_init() after commit d581ebf5


("net: tile: Use helpers from linux/etherdevice.h to check/set MAC").

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>