PCI: Rationalize pci_ats_queue_depth() error checking
PCI: Rationalize pci_ats_queue_depth() error checking

We previously returned -ENODEV for devices that don't support ATS (except
that we always returned 0 for VFs, whether or not they support ATS).

For consistency, always return -EINVAL (not -ENODEV) if the device doesn't
support ATS.  Return zero for VFs that support ATS.

Signed-off-by: Bjorn Helgaas <f10ec01be0c6b54271af5c550cd257810bdf3268@google.com>
Reviewed-by: Joerg Roedel <61aff96566804ea1da8a65de5bcc892ce07caceb@suse.de>
KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs