Bluetooth: Use proper invalid value for tx_power

The core specification defines 127 as the "not available" value (well,
"reserved" for BR/EDR and "not available" for LE - but essentially the
same). Therefore, instead of testing for 0 (which is in fact a valid
value) we should be using this invalid value to test if the tx_power is
available.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index a1a62ba..dedbb1d 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -484,7 +484,7 @@
 		ptr += (name_len + 2);
 	}
 
-	if (hdev->inq_tx_power) {
+	if (hdev->inq_tx_power != HCI_TX_POWER_INVALID) {
 		ptr[0] = 2;
 		ptr[1] = EIR_TX_POWER;
 		ptr[2] = (u8) hdev->inq_tx_power;