completely unify MCS parsing

Luis left two different ways to parse the MCS set,
one of which was completely endianness broken. Fix
this up by using the correct one in both places.
diff --git a/util.c b/util.c
index 50ea9f5..13ebfab 100644
--- a/util.c
+++ b/util.c
@@ -293,7 +293,7 @@
 	return 2;
 }
 
-void print_mcs_index(__u8 *mcs)
+static void print_mcs_index(const __u8 *mcs)
 {
 	unsigned int mcs_bit, prev_bit = -2, prev_cont = 0;
 
@@ -430,3 +430,44 @@
 	PRINT_HT_CAP((cap & BIT(15)), "L-SIG TXOP protection");
 #undef PRINT_HT_CAP
 }
+
+void print_ht_mcs(const __u8 *mcs)
+{
+	/* As defined in 7.3.2.57.4 Supported MCS Set field */
+	unsigned int tx_max_num_spatial_streams, max_rx_supp_data_rate;
+	bool tx_mcs_set_defined, tx_mcs_set_equal, tx_unequal_modulation;
+
+	max_rx_supp_data_rate = ((mcs[10] >> 8) & ((mcs[11] & 0x3) << 8));
+	tx_mcs_set_defined = !!(mcs[12] & (1 << 0));
+	tx_mcs_set_equal = !(mcs[12] & (1 << 1));
+	tx_max_num_spatial_streams = ((mcs[12] >> 2) & 3) + 1;
+	tx_unequal_modulation = !!(mcs[12] & (1 << 4));
+
+	if (max_rx_supp_data_rate)
+		printf("\t\tHT Max RX data rate: %d Mbps\n", max_rx_supp_data_rate);
+	/* XXX: else see 9.6.0e.5.3 how to get this I think */
+
+	if (tx_mcs_set_defined) {
+		if (tx_mcs_set_equal) {
+			printf("\t\tHT TX/RX MCS rate indexes supported:\n");
+			print_mcs_index(mcs);
+		} else {
+			printf("\t\tHT RX MCS rate indexes supported:");
+			print_mcs_index(mcs);
+
+			if (tx_unequal_modulation)
+				printf("\t\tTX unequal modulation supported\n");
+			else
+				printf("\t\tTX unequal modulation not supported\n");
+
+			printf("\t\tHT TX Max spatial streams: %d\n",
+				tx_max_num_spatial_streams);
+
+			printf("\t\tHT TX MCS rate indexes supported may differ\n");
+		}
+	} else {
+		printf("\t\tHT RX MCS rate indexes supported:");
+		print_mcs_index(mcs);
+		printf("\t\tHT TX MCS rates indexes are undefined\n");
+	}
+}