[hns3-1126]net: hns3: handle empty unknown interrupt

[Fred Kimmy]

"[Bug Description]
Since some MSI-X interrupt's status may be cleared by hardware,
so when the driver receives the interrupt, reading
HCLGE_VECTOR0_PF_OTHER_INT_STS_REG register will get an empty
unknown interrupt.

[Steps to Reproduce]
1.load PF & VF drvier
2.run iperf
3.run VF & PF & Global reset

[Actual Results]
reset fail for no interrupt

ethtool -K eth7 rx-gro-hw on
Could not change any device features
ethtool -K eth7 gro off
ethtool -K eth7 gro on
ethtool -K eth7 rx-gro-hw off
etht[151071.202143] hns3 0000:7d:00.7: Set promisc mode fail, status is -16.
ool -K eth7 rx-gro-hw on
Could [151071.211350] device eth7 entered promiscuous mode
not change any device features
[151071.218817] hns3 0000:7d:00.7 eth7: disable vlan filter
ethtool -K eth7 gro off
ethtool[151071.226882] hns3 0000:7d:00.7: set vlan filter fail, ret =-16.
 -K eth7 gro on
ethtool -K eth7[151071.235560] hns3 0000:7d:00.7: set vlan filter fail, ret =-16.
 rx-gro-hw off
ethtool -K eth7 [151071.244241] hns3 0000:7d:00.7: Set promisc mode fail, status is -16.
rx-gro-hw on
Could not change any device features
[Expected Results]
reset ok

[Reproducibility]
Inevitably

[Additional information]
Hardware: D06
Firmware: NA
Kernel: NA

[Resolution]
For this case, the irq handler should enable vector0 interrupt.
This patch also use dev_info() instead of dev_dbg() in the
hclge_check_event_cause(), since this information will be useful
for normal usage."

net: hns3: handle empty unknown interrupt