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>
diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
index d27e8d2..223f240 100644
--- a/drivers/fpga/fpga-mgr.c
+++ b/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;