vty: Implement VTY cfg parsing for current parameters

At this stage, osmo-trx still uses the cmdline parameters top run the
device, but it is already able to parse all the same parameters from a
cfg file through the VTY and filling a trx_ctx structure which will be
later used to drive the device. Device config can be printed in the VTY
with "show trx".

Change-Id: Ie084c1b30b63f91c6e7640832ec1797d9e813832
diff --git a/Transceiver52M/osmo-trx.cpp b/Transceiver52M/osmo-trx.cpp
index dc4e1c8..7bc025f 100644
--- a/Transceiver52M/osmo-trx.cpp
+++ b/Transceiver52M/osmo-trx.cpp
@@ -566,7 +566,7 @@
 
 	setup_signal_handlers();
 
-	g_trx_ctx = talloc_zero(tall_trx_ctx, struct trx_ctx);
+	g_trx_ctx = vty_trx_ctx_alloc(tall_trx_ctx);
 
 #ifdef HAVE_SSE3
 	printf("Info: SSE3 support compiled in");