trx_validate_config(): Fix validation of rx_sps

Change-Id: I7e932cff59335add09c76caba6f9ac1e7cf69022
Fixes: Coverity CID#188871
diff --git a/Transceiver52M/osmo-trx.cpp b/Transceiver52M/osmo-trx.cpp
index d01a4cf..7f72c47 100644
--- a/Transceiver52M/osmo-trx.cpp
+++ b/Transceiver52M/osmo-trx.cpp
@@ -376,7 +376,7 @@
 
 	/* Force 4 SPS for EDGE or multi-ARFCN configurations */
 	if ((trx->cfg.egprs || trx->cfg.multi_arfcn) &&
-	    (trx->cfg.tx_sps!=4 || trx->cfg.tx_sps!=4)) {
+	    (trx->cfg.tx_sps!=4 || trx->cfg.rx_sps!=4)) {
 		LOG(ERROR) << "EDGE and Multi-Carrier options require 4 tx and rx sps. Check you config.";
 		return -1;
 	}