[ath] Add counters for STBC TX and LDPC TX.

This is a big no-op until the TX path changes to enable LDPC TX are
added.

sys/dev/ath/if_ath_sysctl.c

@@ -1285,6 +1285,12 @@ ath_sysctl_stats_attach(struct ath_softc *sc)
 	SYSCTL_ADD_UINT(ctx, child, OID_AUTO, "ast_rx_stbc",
 	    CTLFLAG_RD, &sc->sc_stats.ast_rx_stbc, 0,
 	    "Number of STBC frames received");
+	SYSCTL_ADD_UINT(ctx, child, OID_AUTO, "ast_tx_stbc",
+	    CTLFLAG_RD, &sc->sc_stats.ast_tx_stbc, 0,
+	    "Number of STBC frames transmitted");
+	SYSCTL_ADD_UINT(ctx, child, OID_AUTO, "ast_tx_ldpc",
+	    CTLFLAG_RD, &sc->sc_stats.ast_tx_ldpc, 0,
+	    "Number of LDPC frames transmitted");
 	
 	/* Attach the RX phy error array */
 	ath_sysctl_stats_attach_rxphyerr(sc, child);

sys/dev/ath/if_athioctl.h

@@ -166,7 +166,9 @@ struct ath_stats {
 	u_int32_t	ast_tx_node_psq_overflow;
 	u_int32_t	ast_rx_stbc;		/* RX STBC frame */
 	u_int32_t	ast_tx_nodeq_overflow;	/* node sw queue overflow */
-	u_int32_t	ast_pad[12];
+	u_int32_t	ast_tx_ldpc;		/* TX LDPC frame */
+	u_int32_t	ast_tx_stbc;		/* TX STBC frame */
+	u_int32_t	ast_pad[10];
 };
 
 #define	SIOCGATHSTATS	_IOWR('i', 137, struct ifreq)