ThunderX support broken since r336520

[kraileth at elderlinux.org]

Quote John F Carr <jfc at mit.edu>:

>
> In vt_efifb_probe I see there's a hook to disable:
>
> 	TUNABLE_INT_FETCH("hw.syscons.disable", &disabled);
> 	if (disabled != 0)
> 		return (CN_DEAD);
>

Just confirming that this works as expected.

Simply setting a tunable in /boot/loader.conf before booting into  
-CURRENT is of course even easier than having a custom kernel. Thanks  
John!