ASoC: rsnd: call missing snd_soc_unregiter_component/platform()

Current Renesas R-Car sound driver doesn't call
snd_soc_unregiter_component/platform() in .remove.
This patch call these functions.

Reported-by: Nguyen Viet Dung <nv-dung@jinso.co.jp>
Reported-by: Bui Duc Phuc <bd-phuc@jinso.co.jp>
Reported-by: Cao Minh Hiep <cm-hiep@jinso.co.jp>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>