hw/pci-host/pam: Make init_pam() usage more readable

hw/pci-host/pam: Make init_pam() usage more readable

Unlike pam_update() which takes the subject -- PAMMemoryRegion -- as
first argument, init_pam() takes it as fifth (!) argument. This makes it
quite hard to figure out what an init_pam() invocation actually
initializes. By moving the subject to the front this should become
clearer.

While at it, lower the DeviceState parameter to Object, also
communicating more clearly that this parameter is just the owner rather
than some (heavy?) dependency.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230213162004.2797-8-shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>