vdpa/octeon_ep: handle device config change events

vdpa/octeon_ep: handle device config change events

The first interrupt of the device is used to notify the host about
device configuration changes, such as link status updates. The ISR
configuration area is updated to indicate a config change event when
triggered.

Signed-off-by: Satha Rao <skoteshwar@marvell.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Shijith Thotton <sthotton@marvell.com>
Message-Id: <20250103153226.1933479-2-sthotton@marvell.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>