fpga: add attribute groups

Make it easy to add attributes to low level FPGA drivers the right
way.  Add attribute groups pointers to structures that are used when
registering a manager, bridge, or group.  When the low level driver
registers, set the device attribute group.  The attributes are
created in device_add.

Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fpga/fpga-bridge.c

@@ -367,6 +367,7 @@ int fpga_bridge_register(struct device *dev, const char *name,
 	bridge->priv = priv;
 
 	device_initialize(&bridge->dev);
+	bridge->dev.groups = br_ops->groups;
 	bridge->dev.class = fpga_bridge_class;
 	bridge->dev.parent = dev;
 	bridge->dev.of_node = dev->of_node;

drivers/fpga/fpga-mgr.c

@@ -569,6 +569,7 @@ int fpga_mgr_register(struct device *dev, const char *name,
 
 	device_initialize(&mgr->dev);
 	mgr->dev.class = fpga_mgr_class;
+	mgr->dev.groups = mops->groups;
 	mgr->dev.parent = dev;
 	mgr->dev.of_node = dev->of_node;
 	mgr->dev.id = id;

drivers/fpga/fpga-region.c

@@ -173,6 +173,7 @@ int fpga_region_register(struct device *dev, struct fpga_region *region)
 	mutex_init(&region->mutex);
 	INIT_LIST_HEAD(&region->bridge_list);
 	device_initialize(&region->dev);
+	region->dev.groups = region->groups;
 	region->dev.class = fpga_region_class;
 	region->dev.parent = dev;
 	region->dev.of_node = dev->of_node;