fb: Remove unused FBIOGXINFO ioctl

[manu]

Summary

Commit 6d1699583d7e added the FBIOGXINFO ioctl and said that implementation
in driver will come later.
Since it was in 2001 I think we can remove this.

MFC after: 2 weeks
Sponsored by: Beckhoff Automation GmbH & Co. KG

[emaste]

Merge with D33220? They both come from R10:6d1699583d7e. In fact, should that commit just be reverted?

[manu]

In D33218#750760, @emaste wrote:

Merge with D33220? They both come from R10:6d1699583d7e. In fact, should that commit just be reverted?

I'll check if this commit can be reverted directly, if that's the case I'll do that and point to this rev.
If not I'm ok with merging the diffs.