firmware: arm_ffa: Stash ffa_device instead of notify_type in notifier_cb_info

Currently, we store the type of the notification in the notifier_cb_info
structure that is put into the hast list to identify if the notification
block is for the secure partition or the non secure VM.

In order to support framework notifications to reuse the hash list and
to avoid creating one for each time, we need store the ffa_device pointer
itself as the same notification ID in framework notifications can be
registered by multiple FF-A devices.

Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
Message-Id: <20250217-ffa_updates-v3-15-bd1d9de615e7@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>