enetc: Remove unused variable 'enetc_drv_name'

commit ed0a72e0

 ("net/freescale: Clean drivers from static versions")
leave behind this, remove it .

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>