ASoC: Provide a dummy wrapper of snd_soc_set_dmi_name()

For systems without DMI, it makes no sense to have the code.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>