Bluetooth: Update hci_le_scan to use HCI request

This patch changes hci_le_scan helper so it uses the HCI request
framework to enable LE scanning.

Also, the LE scanning disable timeout was removed from the helper
and it is now handled in mgmt start_discovery code.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Merge LE-only and interleaved cases

This patch merges the LE-only and interleaved discovery type cases.
Since hci_le_scan helper uses the HCI request framework, those cases
are pretty much the same now.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Remove timeout handling from hci_cancel_le_scan

This patch moves the LE scanning timeout handling from hci_cancel_
le_scan helper to stop_discovery.

Since we want discovery code handling LE scanning timeout, we should
handle it in stop_discovery instead of hci_cancel_le_scan.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Remove LE scan work

This patch removes the LE scan work and all code related to it. We
now use the HCI request framework to enable LE scanning so the LE
scan work is no longer needed.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Change LE scanning timeout macros

Define LE scanning timeout macros in jiffies just like we do for
others timeout macros.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Add LE scan type macros

This patch adds macros for active and passive LE scan type values. It
also removes the LE_SCAN_TYPE macro since it is not used anymore.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>