Transceiver: Allow sending negative nominal tx power in RSP NOMTXPOWER
Transceiver: Allow sending negative nominal tx power in RSP NOMTXPOWER

Some SDR devices under some bands may provide only under 0 dBm Tx Power.

Change-Id: I8cecb7a37eb80db341a624eb7b826180eac4a1d4

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