Bluetooth: Check scan state before disabling during suspend

Check current scan state by checking HCI_LE_SCAN flag and send scan
disable command only if scan is already enabled.

Signed-off-by: Manish Mandlik <mmandlik@google.com>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>