net/hns3: check quantity limiter support before using it

net/hns3: check quantity limiter support before using it

If hardware does not support QL (quantity limiter), the int_ql_max
is 0, software should confirm ql_value is less than int_ql_max
before write QL register. This patch add check of int_ql_max
value from firmware and delete the unused variable coalesce_mode.

Fixes: 27911a6e62e5 ("net/hns3: add Rx interrupts compatibility")
Cc: stable@dpdk.org
Signed-off-by: Hongbo Zheng <zhenghongbo3@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>