Transceiver: Avoid noise calculation formula in 2 branches in pullRadioVector
Transceiver: Avoid noise calculation formula in 2 branches in pullRadioVector

Makes code easier to follow and will help in forthcoming refactoring
once idle frames are supported.

Change-Id: I56c84e9684ca460efd6c983d7e95d8e455bcac69

osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx