net: mvpp2: cls: Remove unnessesary check in mvpp2_ethtool_cls_rule_ins

Fix smatch warning:

drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c:1236
 mvpp2_ethtool_cls_rule_ins() warn: unsigned 'info->fs.location' is never less than zero.

'info->fs.location' is u32 type, never less than zero.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>