Bluetooth: Move scope of state_to_string

Function state_to_string will be used in other files in debug
statements.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

include/net/bluetooth/bluetooth.h

@@ -131,6 +131,33 @@ enum {
 	BT_CLOSED
 };
 
+/* If unused will be removed by compiler */
+static inline const char *state_to_string(int state)
+{
+	switch (state) {
+	case BT_CONNECTED:
+		return "BT_CONNECTED";
+	case BT_OPEN:
+		return "BT_OPEN";
+	case BT_BOUND:
+		return "BT_BOUND";
+	case BT_LISTEN:
+		return "BT_LISTEN";
+	case BT_CONNECT:
+		return "BT_CONNECT";
+	case BT_CONNECT2:
+		return "BT_CONNECT2";
+	case BT_CONFIG:
+		return "BT_CONFIG";
+	case BT_DISCONN:
+		return "BT_DISCONN";
+	case BT_CLOSED:
+		return "BT_CLOSED";
+	}
+
+	return "invalid state";
+}
+
 /* BD Address */
 typedef struct {
 	__u8 b[6];