ASoC: topology: Modify clock gating parameter parsing to switch

This improves the coding style of this piece of code.

Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Pan Xiuli <xiuli.pan@linux.intel.com>
Cc: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Cc: alsa-devel@alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>