airoha: Fix typo in TX counter.

The TX drop counter will incorrectly be overwritten
by the RX drop counter.

This commit solves this behaviour.

econet/ecnt_prvt.c

@@ -103,7 +103,7 @@ int ecnt_prvt_get_port_statistics(uint32_t port,
 	if (rstats != NULL) {
 #define FILL_RSTATS_FOR_DIRECTION(__rmon_field, __ecnt_prefix) \
 		do { \
-			rstats->tx.drop_events = \
+			rstats->__rmon_field.drop_events = \
 				portcnt.__ecnt_prefix ## DropFramesCnt; \
 			rstats->__rmon_field.bytes = \
 				portcnt.__ecnt_prefix ## BytesCnt_Lo; \