net: hns3: Add missing break in misc_irq_handle

There is a break missing in the switch/case handling in
hclge_misc_irq_handle, which causes the log to output
uncorrectly.

This patch adds the missing break, and change the dev_dbg
to dev_warn in order to better catch the error.

Fixes: c1a81619 ("net: hns3: Add mailbox interrupt handling to PF driver")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>