fpga: dfl: afu: add error reporting support.

Error reporting is one important private feature, it reports error
detected on port and accelerated function unit (AFU). It introduces
several sysfs interfaces to allow userspace to check and clear
errors detected by hardware.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Moritz Fischer <mdf@kernel.org>

drivers/fpga/dfl-afu.h

@@ -101,4 +101,9 @@ int afu_dma_unmap_region(struct dfl_feature_platform_data *pdata, u64 iova);
 struct dfl_afu_dma_region *
 afu_dma_region_find(struct dfl_feature_platform_data *pdata,
 		    u64 iova, u64 size);
+
+extern const struct dfl_feature_ops port_err_ops;
+extern const struct dfl_feature_id port_err_id_table[];
+extern const struct attribute_group port_err_group;
+
 #endif /* __DFL_AFU_H */