net: hns3: add NULL pointer check for hns3_set/get_ringparam()

mainline inclusion
from mainline-net-5.17
commit 4d07c593
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4YXIM
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4d07c5936c25



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When pci devices init failed and haven't reinit, priv->ring is
NULL and hns3_set/get_ringparam() will access priv->ring. it
causes call trace.

So, add NULL pointer check for hns3_set/get_ringparam() to
avoid this situation.

Fixes: 5668abda ("net: hns3: add support for set_ringparam")
Signed-off-by: Hao Chen <chenhao288@hisilicon.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>