ifconfig: fix gre(4) status

[pouria]

Summary

Set ifr->ifr_name to actually show the
status of gre interface.

Test Plan

create a gre tunnel with a key and option:

sh
ifconfig gre0 create grekey 1 udpencap
ifconfig gre0

[pouria]

@glebius can I MFC this into stable/15 within 3 days?

[zlei]

Looks good to me.

In D55099#1259353, @pouria wrote:

@glebius can I MFC this into stable/15 within 3 days?

Do you actually want to MFC to stable/14 to catch up with 14.4-BETA1 ? I see no problems.

[pouria]

In D55099#1259415, @zlei wrote:

Looks good to me.

In D55099#1259353, @pouria wrote:

@glebius can I MFC this into stable/15 within 3 days?

Do you actually want to MFC to stable/14 to catch up with 14.4-BETA1 ? I see no problems.

You're right. I will. Thank you

[pouria]

So, seems like 14.4-BETA1 checkout happens at February 6.
@glebius I need approval for MFC within 1 day.

[glebius]

Please consider all trivial MFCs approved.