raw/ifpga: support OFS card probing

raw/ifpga: support OFS card probing

PAC N6000 is the first OFS platform, its device id is added to ifpga
device support list.

Previous FPGA platform like Intel PAC N3000 and N5000, FME DFL (Device
Feature List) starts from BAR0 by default, port DFL location is indicated
in PORTn_OFFSET register in FME. In OFS implementation, FME DFL and port
DFL location can be defined individually in PCIe VSEC (Vendor Specific
Extended Capabilities). In this patch, DFL definition is searched in VSEC,
the legacy DFL is used only when DFL VSEC is not present.

In original DFL enumeration process, AFU is expected to locate in port DFL,
but this is not the case in OFS implementation. In this patch, enumeration
can search AFU in any PF/VF which has no FME and port.

Signed-off-by: Wei Huang <wei.huang@intel.com>
Acked-by: Tianfei Zhang <tianfei.zhang@intel.com>
Reviewed-by: Rosen Xu <rosen.xu@intel.com>