ASoC: sta32x: shortcut the for loop to get ir and mcs

There is exactly one match or no match at all during the for loop iteration,
thus we can break from the for loop once a match is found.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>