ASoC: Fix __iomem annotation for IDMA registers

We always store the register address as __iomem but pass it around as a
plain void * which upsets sparse.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/samsung/idma.c b/sound/soc/samsung/idma.c
index 6ca3d8c..baf97eb 100644
--- a/sound/soc/samsung/idma.c
+++ b/sound/soc/samsung/idma.c
@@ -403,7 +403,7 @@
 	return ret;
 }
 
-void idma_reg_addr_init(void *regs, dma_addr_t addr)
+void idma_reg_addr_init(void __iomem *regs, dma_addr_t addr)
 {
 	spin_lock_init(&idma.lock);
 	idma.regs = regs;