net: hns3: sync rx ring head in echo common pull

When the driver processes rx packets, the head pointer is updated only
after the number of received packets reaches 16. However, hardware
relies on the head pointer to calculate the number of FBDs. As a result,
the hardware calculates the FBD incorrectly. Therefore, the driver
proactively updates the head pointer in each common poll to ensure that
the number of FBDs calculated by the hardware is correct.

Fixes: 68752b24 ("net: hns3: schedule the polling again when allocation fails")
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>