TRX: schedule: remove dead code

the check whether or not to send a dummy burst is done already in
trx_sched_dl_burst(), so no need to have commented-out code doing that
again.

src/osmo-bts-trx/scheduler.c

@@ -2889,14 +2889,8 @@ static int trx_sched_fn(uint32_t fn)
 			/* get burst for FN */
 			bits = trx_sched_dl_burst(l1h, tn, fn);
 			if (!bits) {
-#if 0
-				/* if no bits, send dummy burst with no gain */
-				bits = dummy_burst;
-				gain = 128;
-#else
 				/* if no bits, send no burst */
 				continue;
-#endif
 			} else
 				gain = 0;
 			trx_if_data(l1h, tn, fn, gain, bits);