PCI: hv: Return zero, not garbage, when reading PCI_INTERRUPT_PIN

PCI: hv: Return zero, not garbage, when reading PCI_INTERRUPT_PIN

The intent of the code snippet is to always return 0 for both
PCI_INTERRUPT_LINE and PCI_INTERRUPT_PIN.

The check misses PCI_INTERRUPT_PIN. This patch fixes that.

This is discovered by this call in VFIO:

    pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);

The old code does not set *val to 0 because it misses the check for
PCI_INTERRUPT_PIN. Garbage is returned in that case.

Fixes: 4daace0d8ce8 ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs")
Link: https://lore.kernel.org/linux-pci/20240701202606.129606-1-wei.liu@kernel.org
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Cc: stable@kernel.org