hw/vfio/ap: Storing event information for an AP configuration change event

hw/vfio/ap: Storing event information for an AP configuration change event

These functions can be invoked by the function that handles interception
of the CHSC SEI instruction for requests indicating the accessibility of
one or more adjunct processors has changed.

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20250609164418.17585-4-rreyes@linux.ibm.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>