How to implement I210 errata workaround case 31?

[Zhangbin]

This is a follow-up to anther discussion: 

I210 TX qeueu stalled randomly during long-term operation 

@Devi_Intel 

Very strange I cannot reply on that discussion, so post a new one there:

I210 spec update suggests user to disable ipv6 extension (set bit 16 in RFCTL register) to fix the I210 errata case 31:

but the bit 16 of RFCTL in I210 datasheet is stated as reserved, there is no meaning to set bit16 to 1:

So could you please kindly suggest me how to follow I210 spec update to implement the workaround of I210 spec update errata case 31?

Thanks.

Sam