firmware: memmap: use default_groups in kobj_type

There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field.  Move the firmware memmap sysfs code to use default_groups field
which has been the preferred way since aa30f47cf6 ("kobject: Add
support for default attribute groups to kobj_type") so that we can soon
get rid of the obsolete default_attrs field.

Link: https://lore.kernel.org/r/20220105175650.2640758-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/firmware/memmap.c

@@ -69,6 +69,7 @@ static struct attribute *def_attrs[] = {
 	&memmap_type_attr.attr,
 	NULL
 };
+ATTRIBUTE_GROUPS(def);
 
 static const struct sysfs_ops memmap_attr_ops = {
 	.show = memmap_attr_show,
@@ -118,7 +119,7 @@ static void __meminit release_firmware_map_entry(struct kobject *kobj)
 static struct kobj_type __refdata memmap_ktype = {
 	.release	= release_firmware_map_entry,
 	.sysfs_ops	= &memmap_attr_ops,
-	.default_attrs	= def_attrs,
+	.default_groups	= def_groups,
 };
 
 /*