net: ixp4xx_hss: remove redundant spaces

According to the chackpatch.pl,
space prohibited after that open parenthesis '('.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>