octphy: Look-up the right timeslot and then the logical chan
octphy: Look-up the right timeslot and then the logical chan

Use the right identifier for the timeslot and not the trx number
which would always use ts==0 on the first trx. This should fix
ciphering issues for TS>0 (e.g. SDCCH8 on TS==1)

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