Bluetooth: Prevent unintended pause by checking if advertising is active

When PA Create Sync is enabled, advertising resumes unexpectedly.
Therefore, it's necessary to check whether advertising is currently
active before attempting to pause it.

  < HCI Command: LE Add Device To... (0x08|0x0011) plen 7  #1345 [hci0] 48.306205
  		Address type: Random (0x01)
  		Address: 4F:84:84:5F:88:17 (Resolvable)
  		Identity type: Random (0x01)
  		Identity: FC:5B:8C:F7:5D:FB (Static)
  < HCI Command: LE Set Address Re.. (0x08|0x002d) plen 1  #1347 [hci0] 48.308023
  		Address resolution: Enabled (0x01)
  ...
  < HCI Command: LE Set Extended A.. (0x08|0x0039) plen 6  #1349 [hci0] 48.309650
  		Extended advertising: Enabled (0x01)
  		Number of sets: 1 (0x01)
  		Entry 0
  		Handle: 0x01
  		Duration: 0 ms (0x00)
  		Max ext adv events: 0
  ...
  < HCI Command: LE Periodic Adve.. (0x08|0x0044) plen 14  #1355 [hci0] 48.314575
  		Options: 0x0000
  		Use advertising SID, Advertiser Address Type and address
  		Reporting initially enabled
  		SID: 0x02
  		Adv address type: Random (0x01)
  		Adv address: 4F:84:84:5F:88:17 (Resolvable)
  		Identity type: Random (0x01)
  		Identity: FC:5B:8C:F7:5D:FB (Static)
  		Skip: 0x0000
  		Sync timeout: 20000 msec (0x07d0)
  		Sync CTE type: 0x0000

Fixes: ad383c2c ("Bluetooth: hci_sync: Enable advertising when LL privacy is enabled")
Signed-off-by: Yang Li <yang.li@amlogic.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>