Normal Abis RSL MEasurement Results contain only the "MS Timing Offset
IE" in units of full symbols. In some use cases it is important to have
higher-accuracy timing information exposed to the BSC.
We do this by adding the average timing offset value during the last
measurement interval in 1/256th symbol accuracy to the "Supplementary
MEasuremen Information" part of the TS 48.058 9.3.25 Uplink Measurements
IE.
In order to avoid any compatibility issues, this feature is only enabled
if the new vty config command "supp-meas-info toa256" at the bts node
is enabled.
Change-Id: Ie85e53b47d4041cc4e6d7b78406ae8b79b2d9397