PCI: Support SR-IOV on any function type

Previously, we only supported SR-IOV on PCI Express Endpoints and Root
Complex Integrated Endpoints.  This restriction has been present since
d1b054da ("PCI: initialize and release SR-IOV capability") added SR-IOV
support, but the spec does not require it.  In fact, the SR-IOV spec r1.1,
sec 3.3, says the SR-IOV extended capability may be present for any Type 0
function.

Remove the function type test, so we can support SR-IOV on any function.

Some AMD GPUs have display outputs, use the VGA class code, are Legacy
Endpoints, and support SR-IOV.  This change allows Linux to enable SR-IOV
on these devices.

[bhelgaas: changelog]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=112221


Signed-off-by: Kelly Zytaruk <kelly.zytaruk@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>