tbf: Remove IMSI handling from trigger_dl_ass

Currently the BTS::trigger_dl_ass() method assigns the IMSI to the MS
object. This should be (and is already) done earlier where the MS
object is retrieved/created.

This commit removes the corresponding code along with the 'imsi'
parameter from trigger_dl_ass.

Sponsored-by: On-Waves ehf
4 files changed