bcache: 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 bcache sysfs code to use default_groups field which has
been the preferred way since aa30f47cf666 ("kobject: Add support for
default attribute groups to kobj_type") so that we can soon get rid of
the obsolete default_attrs field.

Cc: Kent Overstreet <[e-mail]>
Cc: [e-mail]
Acked-by: Coly Li <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/md/bcache/stats.c

···
 {
 }
 
-static struct attribute *bch_stats_files[] = {
+static struct attribute *bch_stats_attrs[] = {
 	&sysfs_cache_hits,
 	&sysfs_cache_misses,
 	&sysfs_cache_bypass_hits,
···
 	&sysfs_bypassed,
 	NULL
 };
+ATTRIBUTE_GROUPS(bch_stats);
 static KTYPE(bch_stats);
 
 int bch_cache_accounting_add_kobjs(struct cache_accounting *acc,

drivers/md/bcache/sysfs.c

···
 	return size;
 }
 
-static struct attribute *bch_cached_dev_files[] = {
+static struct attribute *bch_cached_dev_attrs[] = {
 	&sysfs_attach,
 	&sysfs_detach,
 	&sysfs_stop,
···
 	&sysfs_backing_dev_uuid,
 	NULL
 };
+ATTRIBUTE_GROUPS(bch_cached_dev);
 KTYPE(bch_cached_dev);
 
 SHOW(bch_flash_dev)
···
 }
 STORE_LOCKED(bch_flash_dev)
 
-static struct attribute *bch_flash_dev_files[] = {
+static struct attribute *bch_flash_dev_attrs[] = {
 	&sysfs_unregister,
 #if 0
 	&sysfs_data_csum,
···
 	&sysfs_size,
 	NULL
 };
+ATTRIBUTE_GROUPS(bch_flash_dev);
 KTYPE(bch_flash_dev);
 
 struct bset_stats_op {
···
 {
 }
 
-static struct attribute *bch_cache_set_files[] = {
+static struct attribute *bch_cache_set_attrs[] = {
 	&sysfs_unregister,
 	&sysfs_stop,
 	&sysfs_synchronous,
···
 	&sysfs_clear_stats,
 	NULL
 };
+ATTRIBUTE_GROUPS(bch_cache_set);
 KTYPE(bch_cache_set);
 
-static struct attribute *bch_cache_set_internal_files[] = {
+static struct attribute *bch_cache_set_internal_attrs[] = {
 	&sysfs_active_journal_entries,
 
 	sysfs_time_stats_attribute_list(btree_gc, sec, ms)
···
 	&sysfs_feature_incompat,
 	NULL
 };
+ATTRIBUTE_GROUPS(bch_cache_set_internal);
 KTYPE(bch_cache_set_internal);
 
 static int __bch_cache_cmp(const void *l, const void *r)
···
 }
 STORE_LOCKED(bch_cache)
 
-static struct attribute *bch_cache_files[] = {
+static struct attribute *bch_cache_attrs[] = {
 	&sysfs_bucket_size,
 	&sysfs_block_size,
 	&sysfs_nbuckets,
···
 	&sysfs_cache_replacement_policy,
 	NULL
 };
+ATTRIBUTE_GROUPS(bch_cache);
 KTYPE(bch_cache);

drivers/md/bcache/sysfs.h

···
 		.show	= type ## _show,				\
 		.store	= type ## _store				\
 	}),								\
-	.default_attrs	= type ## _files				\
+	.default_groups	= type ## _groups				\
 }
 
 #define SHOW(fn)							\