pci/shpc: Do not unparent in instance_finalize()

pci/shpc: Do not unparent in instance_finalize()

Children are automatically unparented so manually unparenting is
unnecessary.

Worse, automatic unparenting happens before the instance_finalize()
callback of the parent gets called, so object_unparent() calls in
the callback will refer to objects that are already unparented, which
is semantically incorrect.

Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20251027-shpc-v1-1-00e9b20a355d@rsg.ci.i.u-tokyo.ac.jp>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251027-shpc-v1-1-00e9b20a355d@rsg.ci.i.u-tokyo.ac.jp>