ASoC: sta32x: Fix array access overflow

Preset EQ enum of sta32x codec driver declares too many number of
items and it may lead to the access over the actual array size.

Use SOC_ENUM_SINGLE_DECL() helper and it's automatically fixed.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org