With the last commit we moved to using the hci_sync queue for "Create
Connection" requests, removing the need for retrying the paging after
finished/failed "Create Connection" requests and after the end of
inquiries.

hci_conn_check_pending() was used to trigger this retry, we can remove it
now.

Note that we can also remove the special handling for COMMAND_DISALLOWED
errors in the completion handler of "Create Connection", because "Create
Connection" requests are now always serialized.

This is somewhat reverting commit 4c67bc74 ("[Bluetooth] Support
concurrent connect requests").

With this, the BT_CONNECT2 state of ACL hci_conn objects should now be
back to meaning only one thing: That we received a "Connection Request"
from another device (see hci_conn_request_evt), but the response to that
is going to be deferred.
Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>