[subscr] Remove the struct gsm_bts pointer from subscriber

The pointer was initially added to support to open a lchan
by using the gsm_subscriber structure. We would have restored
the struct gsm_bts from the db when loading the subscriber.

Instead we will dynamically resolve the gsm_bts and might end
up paging multiple bts in the same (stored/old) location area
until it answers.
2 files changed