net: hns3: remove an unnecessary check in hclge_set_umv_space()

Since hclge_set_umv_space() is only called by hclge_init_umv_space(),
parameter 'allocated_size' will not be NULL.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>