ASoC: omap-mcpdm: Remove useless ressource get.

Remove unused memory ressource get from McPDM driver.

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>