Bluetooth: Introduce "New Connection Parameter" Event

This patch introduces a new Mgmt event called "New Connection Parameter".
This event indicates to userspace the connection parameters values the
remote device requested.

The user may store these values and load them into kernel (an upcoming
patch will introduce a Mgmt command to do that). This way, next time a
connection is established to that device, the kernel will use those
parameters values instead of the default ones.

This event is sent when the remote device requests new connection
parameters through Link Layer or L2CAP connection parameter update
procedures.

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