net: hns3: remove redundant print on ENOMEM

All kmalloc-based functions print enough information on failures.
So this patch removes the log in hclge_get_dfx_reg() when returns
ENOMEM.

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