pci: Honour wmask when resetting PCI_INTERRUPT_LINE

pci: Honour wmask when resetting PCI_INTERRUPT_LINE

The pci_do_device_reset() function (called from pci_device_reset)
clears the PCI_INTERRUPT_LINE config reg of devices on the bus but did
this without taking wmask into account. We'll have a device model now
that needs to set a constant value for this reg and this patch allows
to do that without additional workaround in device emulation to
reverse the effect of this PCI bus reset function.

Suggested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-id: 20200313082444.2439-4-mark.cave-ayland@ilande.co.uk
Signed-off-by: John Snow <jsnow@redhat.com>