firmware: arm_ffa: Implement the notification bind and unbind interface

A receiver endpoint must bind a notification to any sender endpoint
before the latter can signal the notification to the former. The receiver
assigns one or more doorbells to a specific sender. Only the sender can
ring these doorbells.

A receiver uses the FFA_NOTIFICATION_BIND interface to bind one or more
notifications to the sender. A receiver un-binds a notification from a
sender endpoint to stop the notification from being signaled. It uses
the FFA_NOTIFICATION_UNBIND interface to do this.

Allow the FF-A driver to be able to bind and unbind a given notification
ID to a specific partition ID. This will be used to register and
unregister notification callbacks from the FF-A client drivers.

Link: https://lore.kernel.org/r/20231005-ffa_v1-1_notif-v4-3-cddd3237809c@arm.com


Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>