DEVELOPERS: Fix warning with get-developers

erlang-p1-iconv does not exist as a package in buildroot and cause warning
with get-developers :

./utils/get-developers -p erlang-p1-iconv
WARNING: 'package/erlang-p1-iconv/' doesn't match any file

Signed-off-by: Joris Offouga <offougajoris@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -1264,7 +1264,6 @@ F:	package/erlang-jose/
 F:	package/erlang-lager/
 F:	package/erlang-p1-acme/
 F:	package/erlang-p1-cache-tab/
-F:	package/erlang-p1-iconv/
 F:	package/erlang-p1-mqtree/
 F:	package/erlang-p1-oauth2/
 F:	package/erlang-p1-pkix/