PCI/AER: Factor out interrupt toggling into helpers

There are many places that enable and disable AER interrupt, so move
them into helpers.

Link: https://lore.kernel.org/r/20230512000014.118942-1-kai.heng.feng@canonical.com


Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>