soundwire: sysfs: move sdw_slave_dev_attr_group into the existing list of groups

soundwire: sysfs: move sdw_slave_dev_attr_group into the existing list of groups

The sysfs logic already creates a list of groups for the device, so add
the sdw_slave_dev_attr_group group to that list instead of having to do
a two-step process of adding a group list and then an individual group.

This is a step on the way to moving all of the sysfs attribute handling
into the default driver core attribute group logic so that the soundwire
core does not have to do any of it manually.

Cc: Vinod Koul <vkoul@kernel.org>
Cc: Bard Liao <yung-chuan.liao@linux.intel.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Sanyog Kale <sanyog.r.kale@intel.com>
Cc: alsa-devel@alsa-project.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-By: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Link: https://lore.kernel.org/r/2024013029-afternoon-suitably-cb59@gregkh
Signed-off-by: Vinod Koul <vkoul@kernel.org>