Add support for DIR-Link DIR-615 D

I have a router D-Link DIR-615 D3 and wants to have it supported by FF. I built a SW for it and have it running (ID 51018) for several days without problems.

assigned to @Erik

changed title from Add support for DIR-Link 615 D to Add support for DIR-Link DIR-615 D

created merge request !143 (merged) to address this issue

mentioned in merge request !143 (merged)

closed with merge request !143 (merged)

mentioned in commit 5c9ebde7