Changes

Increase per PDR (F-TEID) hashtable size

In tunmap scenario there's usually 2 PDRs/local-F-TEIDs per session,
hence it makes sense to at least double the hashtable size with respect
to session hashtable. In here we actually multiply it by 2 twice since
this is actually global and not per peer, hence we account for multiple
peers.

Change-Id: I7ee3e875020d707c05e13ee70952174ca4daad30