s390/sclp_sd: 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 sclp_sd sysfs code to use default_groups field which
has been the preferred way since commit 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: Vasily Gorbik <[e-mail]>
Cc: Christian Borntraeger <[e-mail]>
Cc: Alexander Gordeev <[e-mail]>
Cc: Peter Oberparleiter <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Heiko Carstens <[e-mail]>

drivers/s390/char/sclp_sd.c

···
 	&reload_attr.attr,
 	NULL,
 };
+ATTRIBUTE_GROUPS(sclp_sd_file_default);
 
 static struct kobj_type sclp_sd_file_ktype = {
 	.sysfs_ops = &kobj_sysfs_ops,
 	.release = sclp_sd_file_release,
-	.default_attrs = sclp_sd_file_default_attrs,
+	.default_groups = sclp_sd_file_default_groups,
 };
 
 /**