Comment 0 for bug 1859569

[Bug Description]
When a TC's PFC is disabled or enabled, the RX private buffer for
this TC need to be changed too, otherwise this may cause packet
dropped problem.

[Steps to Reproduce]
1.lldpad -d
2.lldptool -L -i eth0 adminStatus=rxtx
3.lldptool -T -i eth0 -V ETS-CFG tsa=0:ets,1:ets,2:ets,3:ets,4:ets,5:ets,6:ets,7:ets up2tc=0:0,1:0,2:1,3:1,4:2,5:2,6:3,7:3 tcbw=25,25,50,0,0,0,0,0
4.down device
5.up

[Actual Results]
up fail

[Expected Results]
up ok

[Reproducibility]
Inevitably

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

[Resolution]
This patch fixes it by calling hclge_buffer_alloc to reallocate
buffer when pfc_en changes.

net: hns3: fix ETS bandwidth validation bug