fpga: dfl: factor out feature device data from platform device data

fpga: dfl: factor out feature device data from platform device data

Add a structure dfl_feature_dev_data to hold the DFL enumeration
info previously held in dfl_feature_platform_data. Allocate the new
structure using device-managed memory whose lifetime is bound to the
lifetime of the physical DFL, e.g., PCIe FPGA device. In a subsequent
commit, this will allow the feature platform device to be completely
destroyed and recreated on port release and assign, respectively, while
retaining the feature data in the new dfl_feature_dev_data structure.

Signed-off-by: Peter Colberg <peter.colberg@intel.com>
Reviewed-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Reviewed-by: Basheer Ahmed Muddebihal <basheer.ahmed.muddebihal@linux.intel.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20241120011035.230574-11-peter.colberg@intel.com
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>