ASoC: arizona: Free speaker thermal IRQs in CODEC remove

The thermal warning IRQs for the speaker are requested in CODEC probe
but never freed. This patch frees them in CODEC remove.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/wm8998.c b/sound/soc/codecs/wm8998.c
index 0123960..449f666 100644
--- a/sound/soc/codecs/wm8998.c
+++ b/sound/soc/codecs/wm8998.c
@@ -1324,6 +1324,8 @@
 
 	priv->core.arizona->dapm = NULL;
 
+	arizona_free_spk(codec);
+
 	return 0;
 }