Bluetooth: Add simple version of Read Advertising Features command

This adds support for the simplest possible version of Read Advertising
Features management command. It allows basic testing of the interface.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
index f3baad5..4d0ccd1 100644
--- a/include/net/bluetooth/mgmt.h
+++ b/include/net/bluetooth/mgmt.h
@@ -517,6 +517,17 @@
 	} entry[0];
 } __packed;
 
+#define MGMT_OP_READ_ADV_FEATURES	0x0003D
+#define MGMT_READ_ADV_FEATURES_SIZE	0
+struct mgmt_rp_read_adv_features {
+	__le32 supported_flags;
+	__u8   max_adv_data_len;
+	__u8   max_scan_rsp_len;
+	__u8   max_instances;
+	__u8   num_instances;
+	__u8   instance[0];
+} __packed;
+
 #define MGMT_EV_CMD_COMPLETE		0x0001
 struct mgmt_ev_cmd_complete {
 	__le16	opcode;