mesh: Remove unused parameters from internal rx functions

mesh: Remove unused parameters from internal rx functions

This removes unused ttl parameter from mesh_model_rx(). The TTL value
is not processed at the access layer, so there is no need to pass it
to a model.
Also, remove "uint32_t dst" parameter from the typedef of
mesh_model_recv_cb: providing a just destination address is sufficient
for internally implemented models (currently, it's only Config Server)

Change-Id: I603aa23a495a40bb804e0a370331d1efd8508270
Signed-off-by: Anupam Roy <anupam.r@samsung.com>