RDMA/irdma: Fix Passthrough mode in VM

RDMA/irdma: Fix Passthrough mode in VM

Using PCI_FUNC macro in a VM, when the device is in passthrough mode does
not provide the real function instance. This means that currently, devices
will not probe unless the instance in the VM matches the instance in the
host.

Fix this by getting the pf_id from the LAN during the probe.

Fixes: a6f904309fc9 ("RDMA/irdma: Register auxiliary driver and implement private channel OPs")
Link: https://lore.kernel.org/r/20220225163211.127-3-shiraz.saleem@intel.com
Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>