Bluetooth: Make start_discovery use HCI transaction

This patch changes start_discovery so it uses the HCI transaction
framework to enable LE scanning. It also changes hci_le_scan helper
which no longer needs to schedule the le_scan work. The timeout
handling was also removed hci_le_scan and is now handled by
start_discovery function.

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 transaction framework to enable LE scanning. The
LE scan work is no longer needed.

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 discovery is using the hci transaction framework, those cases
are pretty much the same now.

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

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

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>