bts-trx: Fix osmocom dyn ts assert hit during Adm State Unlock
bts-trx: Fix osmocom dyn ts assert hit during Adm State Unlock

How to reproduce:
* Configure a TS to be TCH/F_TCH/H_PDCH in osmo-bsc.cfg
* Run the network with osmo-bts-trx, then use osmo-bsc's "rf_locked 1"
* Then, unlock it: "rf_locked 0"
* The following assert will be hit:
Assert failed ts->dyn.pchan_is == ts->dyn.pchan_want /osmo-bts/src/osmo-bts-trx/l1_if.c:349
"""
(gdb) bt
 #0  0x00007ffff5bb9355 in raise () from /usr/lib/libc.so.6
 #1  0x00007ffff5ba2853 in abort () from /usr/lib/libc.so.6
 #2  0x00007ffff6832361 in osmo_panic_default (
    fmt=0x555555814e60 "Assert failed %s %s:%d\n", args=0x7fffffffc6e0)
    at /libosmocore/src/panic.c:49
 #3  0x00007ffff683249d in osmo_panic (
    fmt=0x555555814e60 "Assert failed %s %s:%d\n")
    at /libosmocore/src/panic.c:84
 #4  0x000055555570fdf7 in trx_set_ts (ts=0x7ffff1e6bce8)
    at /osmo-bts/src/osmo-bts-trx/l1_if.c:349
 #5  0x00005555557133c1 in bts_model_chg_adm_state (bts=0x627000000160,
    mo=0x7ffff1e0f8a0, obj=0x7ffff1e0f860, adm_state=2 '\002')
    at /osmo-bts/src/osmo-bts-trx/l1_if.c:681
 #6  0x0000555555769978 in oml_rx_chg_adm_state (bts=0x627000000160,
    msg=0x633000003e00)
    at /osmo-bts/src/common/oml.c:1044
 #7  0x000055555576a8d3 in down_fom (bts=0x627000000160, msg=0x633000003e00)
    at /osmo-bts/src/common/oml.c:1129
 #8  0x0000555555770aed in down_oml (bts=0x627000000160, msg=0x633000003e00)
    at /osmo-bts/src/common/oml.c:1476
 #9  0x00005555557f8174 in sign_link_cb (msg=0x633000003e00)
    at /osmo-bts/src/common/abis.c:188
 #10 0x00007ffff73b5935 in ipaccess_bts_read_cb (link=0x6120000030a0,
--Type <RET> for more, q to quit, c to continue without paging--
    msg=0x633000003e00)
    at /libosmo-abis/src/input/ipaccess.c:980
 #11 0x00007ffff73a1060 in ipa_client_read (link=0x6120000030a0)
    at /libosmo-abis/src/input/ipa.c:72
 #12 0x00007ffff73a2458 in ipa_client_fd_cb (ofd=0x62f000038a50, what=1)
    at /libosmo-abis/src/input/ipa.c:136
 #13 0x00007ffff67ebfa7 in osmo_fd_disp_fds (_rset=0x7fffffffdda0,
    _wset=0x7fffffffde40, _eset=0x7fffffffdee0)
    at /libosmocore/src/select.c:227
 #14 0x00007ffff67ec38c in _osmo_select_main (polling=0)
    at /libosmocore/src/select.c:265
 #15 0x00007ffff67ec46b in osmo_select_main (polling=0)
    at /libosmocore/src/select.c:274
 #16 0x00005555557ef089 in bts_main (argc=7, argv=0x7fffffffe208)
    at /osmo-bts/src/common/main.c:354
 #17 0x00005555556fe621 in main (argc=7, argv=0x7fffffffe208)
    at /osmo-bts/src/osmo-bts-trx/main.c:176
"""

Related: OS#4920
Change-Id: Ia3210e24b921fd0c67f77068b7ef4a65f270cd11

osmocom/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts