dmaengine: ioatdma: 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 ioatdma sysfs code to use default_groups field which has
been the preferred way since aa30f47c ("kobject: Add support for
default attribute groups to kobj_type") so that we can soon get rid of
the obsolete default_attrs field.

Cc: Vinod Koul <vkoul@kernel.org>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20220104163330.1338824-1-gregkh@linuxfoundation.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/ioat/sysfs.c

@@ -158,8 +158,9 @@ static struct attribute *ioat_attrs[] = {
 	&intr_coalesce_attr.attr,
 	NULL,
 };
+ATTRIBUTE_GROUPS(ioat);
 
 struct kobj_type ioat_ktype = {
 	.sysfs_ops = &ioat_sysfs_ops,
-	.default_attrs = ioat_attrs,
+	.default_groups = ioat_groups,
 };