ASoC: jack: Fix warning while make htmldocs caused by soc-jack.c

This patch fix following errors while "make htmldocs" on
linux-next-20141110.

Warning(.//sound/soc/soc-jack.c:126): No description found for
parameter 'zones'
Warning(.//sound/soc/soc-jack.c:126): Excess function parameter
'zone' description in 'snd_soc_jack_add_zones'

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-jack.c

@@ -116,7 +116,7 @@ EXPORT_SYMBOL_GPL(snd_soc_jack_report);
  *
  * @jack:  ASoC jack
  * @count: Number of zones
- * @zone:  Array of zones
+ * @zones:  Array of zones
  *
  * After this function has been called the zones specified in the
  * array will be associated with the jack.