set BS power to Pn == nominal output power

This is only relevant for TRX1, since TRX0 will always opwerate at constant
power.  However, when channels on TRX0 are activated, we should provide
a reasonable BS poewr level.

openbsc/src/abis_rsl.c

@@ -1070,7 +1070,7 @@ static int rsl_rx_chan_rqd(struct msgb *msg)
 	subch = lchan->nr;
 	
 	lchan->ms_power = ms_pwr_ctl_lvl(bts->band, 20 /* dBm == 100mW */);
-	lchan->bs_power = 0x0f; /* 30dB reduction */
+	lchan->bs_power = 0; /* 0dB reduction, output power = Pn */
 	lchan->rsl_cmode = RSL_CMOD_SPD_SIGN;
 	rsl_chan_activate_lchan(lchan, 0x00, rqd_ta);