liquidio: remove set but not used variable 's'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/cavium/liquidio/lio_main.c: In function 'octeon_chip_specific_setup':
drivers/net/ethernet/cavium/liquidio/lio_main.c:1378:8: warning:
 variable 's' set but not used [-Wunused-but-set-variable]

It's not used since commit b6334be6 ("net/liquidio: Delete driver version assignment")

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