ASoC: omap-dmic: Clean up with devm_request_and_ioremap

Clean up dmic code with devm_request_and_ioremap function.

Signed-off-by: Sebastien Guiriec <s-guiriec@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>