ALSA: fix invalid hardware.h include in ac97c for AVR32 architecture

This patch fixes the non-compiling AC97C driver for AVR32 architecture by
include mach/hardware.h only for AT91 architecture. The AVR32 architecture does
not supply the hardware.h include file.
Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
CC: stable@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/atmel/ac97c.c

@@ -33,9 +33,12 @@
 #include <linux/dw_dmac.h>
 
 #include <mach/cpu.h>
-#include <mach/hardware.h>
 #include <mach/gpio.h>
 
+#ifdef CONFIG_ARCH_AT91
+#include <mach/hardware.h>
+#endif
+
 #include "ac97c.h"
 
 enum {