sysmobts: Add the requested TA to the field ACCH header
sysmobts: Add the requested TA to the field ACCH header

Write the requested timing advance into the header. We are currently
using the u8AutoTA mode so the value will be overwritten by the DSP
before the bursts are sent to the MS.

osmocom/osmo-bts,geosphere/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts,telenoobie/osmo-bts,geosphere/osmo-bts