Bluetooth: Check inquiry status before sending one

There is a possibility where HCI_INQUIRY flag is set but we still
send HCI_OP_INQUIRY anyway.

Such a case can be reproduced by connecting to an LE device while
active scanning. When the device is discovered, we initiate a
connection, stop LE Scan, and send Discovery MGMT with status
disabled, but we don't cancel the inquiry.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Sonny Sasaka <sonnysasaka@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>