Bluetooth: Use extended LE Connection if supported

This implements extended LE craete connection and enhanced
LE conn complete event if the controller supports.

For now it is as good as legacy LE connection and event as
no new features in the extended connection is handled.

< HCI Command: LE Extended Create Connection (0x08|0x0043) plen 26
        Filter policy: White list is not used (0x00)
        Own address type: Public (0x00)
        Peer address type: Random (0x01)
        Peer address: DB:7E:2E:1D:85:E8 (Static)
        Initiating PHYs: 0x01
        Entry 0: LE 1M
          Scan interval: 60.000 msec (0x0060)
          Scan window: 60.000 msec (0x0060)
          Min connection interval: 50.00 msec (0x0028)
          Max connection interval: 70.00 msec (0x0038)
          Connection latency: 0 (0x0000)
          Supervision timeout: 420 msec (0x002a)
          Min connection length: 0.000 msec (0x0000)
          Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4
      LE Extended Create Connection (0x08|0x0043) ncmd 2
        Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 31
      LE Enhanced Connection Complete (0x0a)
        Status: Success (0x00)
        Handle: 3585
        Role: Master (0x00)
        Peer address type: Random (0x01)
        Peer address: DB:7E:2E:1D:85:E8 (Static)
        Local resolvable private address: 00:00:00:00:00:00 (Non-Resolvable)
        Peer resolvable private address: 00:00:00:00:00:00 (Non-Resolvable)
        Connection interval: 67.50 msec (0x0036)
        Connection latency: 0 (0x0000)
        Supervision timeout: 420 msec (0x002a)
        Master clock accuracy: 0x00
@ MGMT Event: Device Connected (0x000b) plen 40
        LE Address: DB:7E:2E:1D:85:E8 (Static)
        Flags: 0x00000000
        Data length: 27
        Name (complete): Designer Mouse
        Appearance: Mouse (0x03c2)
        Flags: 0x05
          LE Limited Discoverable Mode
          BR/EDR Not Supported
        16-bit Service UUIDs (complete): 1 entry
          Human Interface Device (0x1812)

Signed-off-by: Jaganath Kanakkassery <jaganathx.kanakkassery@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>