Even if this is true that is still over 4 months away.
The article also has an out because of the MAY in the title:
GTX 980 May Lose The Performance Crown To AMD’s R9 380X in February 2015
If Fiji is what it is expected to be, i.e. a 550mm² GPU with HBM, besting the GTX 980 shouldn't be a problem, as the 290X isn't that far off anyway.
Now, I don't know if the 380X will be based on Fiji or something else, but the latter does appear to be real. Of course, being faster than GM204 is one thing, being faster than GM200 is quite another.