octphy: display hint in case of wrongly configured transceiver number

Making use of the multi-trx feature requires to tell osmo-bts that
more than one transceiver are available. Otherwise it will complain
that not enough transceivers are available. This can be quite
confusing, even a correct config file will fail to parse if it
specifies more transcrivers than available.

This patch adds a hint to the error message so that the user knows
that he should check the -t commandline option

Change-Id: Ifbeacd9d43f7c6cd74a1e1b33288e66828fe843f

src/common/vty.c

@@ -224,6 +224,8 @@ DEFUN(cfg_bts_trx, cfg_bts_trx_cmd,
 	if (!trx) {
 		vty_out(vty, "Unknown TRX %u. Available TRX are: 0..%u%s",
 			trx_nr, bts->num_trx - 1, VTY_NEWLINE);
+		vty_out(vty, "Hint: Check if commandline option -t matches the"
+			"number of available transceivers!%s", VTY_NEWLINE);
 		return CMD_WARNING;
 	}