ASoC: pxa: pxa2xx-i2s: add io.h for IOMEM macro

* fixes
  sound/soc/pxa/pxa2xx-i2s.c:86:2: error: implicit declaration of function 'IOMEM' [-Werror=implicit-function-declaration]
  sound/soc/pxa/pxa2xx-i2s.c:86:2: error: initializer element is not constant
  after 23019a733bb83c8499f192fb428b7e6e81c95a34 removed IOMEM
  definition from arch/arm/mach-pxa/include/mach/hardware.h

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/pxa/pxa2xx-i2s.c b/sound/soc/pxa/pxa2xx-i2s.c
index 609abd5..d085837 100644
--- a/sound/soc/pxa/pxa2xx-i2s.c
+++ b/sound/soc/pxa/pxa2xx-i2s.c
@@ -17,6 +17,7 @@
 #include <linux/delay.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
+#include <linux/io.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/initval.h>