ramips: fix duplicate network setup for dlink,dir-615-h1

In 555ca422 ("ramips: fix D-Link DIR-615 H1 switch port
mapping"), port setup for dir-615-h1 was changed without removing
the old one. This was working as the new one was triggered earlier
than the old one.

(In the meantine, changed sorting during ramips rename patches
actually inversed that order.)

Anyway, just remove the wrong case now.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>