hw/ide/via: implement legacy/native mode switching

hw/ide/via: implement legacy/native mode switching

Allow the VIA IDE controller to switch between both legacy and native modes by
calling pci_ide_update_mode() to reconfigure the device whenever PCI_CLASS_PROG
is updated.

This patch moves the initial setting of PCI_CLASS_PROG from via_ide_realize() to
via_ide_reset(), and removes the direct setting of PCI_INTERRUPT_PIN during PCI
bus reset since this is now managed by pci_ide_update_mode(). This ensures that
the device configuration is always consistent with respect to the currently
selected mode.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-ID: <20231116103355.588580-5-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>