Bluetooth: Discovery parameters per hci_dev

This patch adds discovery parameters to struct hci_dev. This way, we
will be able to configure the discovery parameters per hci device.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Export discovery parameters on debugfs

This patch exports discovery parameters thought debugfs filesystem.
The default values are:

$ cat discovery_parameters
0x01 0x0012 0x0012 10240 5120 0x04 0x08

The file format is the following:
Scanning type
Scanning interval
Scanning window
Scanning duration (in milliseconds) in LE discovery
Scanning duration (in milliseconds) in interleaved discovery
Inquiry length used in interleaved discovery
Inquiry length used in BR/EDR discovery

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Set discovery parameters

This patch adds support for setting discovery parameters through
debugfs filesystem.

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