Bluetooth: hci_core: cleanup struct hci_dev

Remove unused and set but otherwise unused 'discovery_old_state'
and 'sco_last_tx' members of 'struct hci_dev'. The first one is
a leftover after commit 182ee45d ("Bluetooth: hci_sync: Rework
hci_suspend_notifier"); the second one is originated from ancient
2.4.19 and I was unable to find any actual use since that.
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

include/net/bluetooth/hci_core.h

@@ -476,7 +476,6 @@ struct hci_dev {
 	unsigned int	iso_pkts;
 
 	unsigned long	acl_last_tx;
-	unsigned long	sco_last_tx;
 	unsigned long	le_last_tx;
 
 	__u8		le_tx_def_phys;
@@ -528,7 +527,6 @@ struct hci_dev {
 
 	struct discovery_state	discovery;
 
-	int			discovery_old_state;
 	bool			discovery_paused;
 	int			advertising_old_state;
 	bool			advertising_paused;

net/bluetooth/hci_sync.c

@@ -5853,7 +5853,6 @@ static int hci_pause_discovery_sync(struct hci_dev *hdev)
 		return err;
 
 	hdev->discovery_paused = true;
-	hdev->discovery_old_state = old_state;
 	hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
 
 	return 0;