fpga: dfl: Allow Port to be linked to FME's DFL

fpga: dfl: Allow Port to be linked to FME's DFL

Currently we use PORTn_OFFSET to locate PORT DFLs, and PORT DFLs are not
connected FME DFL. But for some cases (e.g. Intel Open FPGA Stack device),
PORT DFLs are connected to FME DFL directly, so we don't need to search
PORT DFLs via PORTn_OFFSET again. If BAR value of PORTn_OFFSET is 0x7
(FME_PORT_OFST_BAR_SKIP) then driver will skip searching the DFL for that
port. If BAR value is invalid, return -EINVAL.

Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Tianfei Zhang <tianfei.zhang@intel.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Link: https://lore.kernel.org/r/20220505100617.703672-1-tianfei.zhang@intel.com
Signed-off-by: Xu Yilun <yilun.xu@intel.com>