ipack: convert bus code to use dev_groups

ipack_device_attr(id_format, "0x%hhu\n");

static struct device_attribute ipack_dev_attrs[] = {

	__ATTR_RO(id),

	__ATTR_RO(id_device),

	__ATTR_RO(id_format),

	__ATTR_RO(id_vendor),

	__ATTR_RO(modalias),

static DEVICE_ATTR_RO(id);

static DEVICE_ATTR_RO(id_device);

static DEVICE_ATTR_RO(id_format);

static DEVICE_ATTR_RO(id_vendor);

static DEVICE_ATTR_RO(modalias);

static struct attribute *ipack_attrs[] = {

	&dev_attr_id.attr,

	&dev_attr_id_device.attr,

	&dev_attr_id_format.attr,

	&dev_attr_id_vendor.attr,

	&dev_attr_modalias.attr,

	NULL,

};

ATTRIBUTE_GROUPS(ipack);

static struct bus_type ipack_bus_type = {

	.name      = "ipack",

	.probe     = ipack_bus_probe,

	.match     = ipack_bus_match,

	.remove    = ipack_bus_remove,

	.dev_attrs = ipack_dev_attrs,

	.dev_groups = ipack_groups,

	.uevent	   = ipack_uevent,

};