ASoC: atmel: sam9g20_wm8731: remove useless include

A mach/ header is included but never used. Simply remove it.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: NBo Shen <voice.shen@atmel.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/atmel/sam9g20_wm8731.c

@@ -47,7 +47,6 @@
 #include <sound/soc.h>
 
 #include <asm/mach-types.h>
-#include <mach/hardware.h>
 
 #include "../codecs/wm8731.h"
 #include "atmel-pcm.h"