fsms: use configurable timers instead of T23042

T23042 was a placeholder for timers to be filled in later. Replace it
with timers that can be configured via VTY.

Previous timeout for the states was 5s, from using the default of 5 for
undefined timers.

* ASSIGNMENT_ST_WAIT_MGW_ENDPOINT_TO_MSC and
  HO_ST_WAIT_MGW_ENDPOINT_TO_MSC:
  * Runs gscon_connect_mgw_to_msc() on enter, which waits for one MGCP
    CRCX or MDCX response (or changes state immediately)
  * Use existing X9 ("Timeout for availability of MGW endpoint"), 5s,
    which is already being used by lchan_rtp_fsm for a similar purpose

* HO_ST_WAIT_RR_HO_DETECT:
  * Handover initiation as described in 3GPP TS 04.08 § 3.4.4.1:
    "The network initiates the handover procedure by sending a HANDOVER
     COMMAND message to the mobile station on the main DCCH. It then
     starts timer T3103."
  * Use existing but unused timer T3103 ("Handover"), 5s

* HO_ST_WAIT_RR_HO_COMPLETE:
  * Handover completion as described in 3GPP TS 04.08 § 3.4.4.3:
    "When receiving the HANDOVER COMPLETE message, the network stops
     timer T3103 and releases the old channels."
  * Continue using T3103 with keep_timer = true

Closes: OS#5787
Change-Id: Id0d4d0788f609f3272fc81c80a754383dde25c16
---
M src/osmo-bsc/assignment_fsm.c
M src/osmo-bsc/handover_fsm.c
2 files changed, 4 insertions(+), 4 deletions(-)