[ARM] pxa: move AC97 register definitions into dedicated regs-ac97.h

The optimal change would be to move the AC97 register definitions into
the AC97 driver, unfortunately, the registers are shared between several
files. Move them into a dedicated regs-ac97.h first.

Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/sound/soc/pxa/pxa2xx-ac97.c b/sound/soc/pxa/pxa2xx-ac97.c
index a7a3a9c..5e72739 100644
--- a/sound/soc/pxa/pxa2xx-ac97.c
+++ b/sound/soc/pxa/pxa2xx-ac97.c
@@ -21,6 +21,7 @@
 
 #include <mach/hardware.h>
 #include <mach/pxa-regs.h>
+#include <mach/regs-ac97.h>
 
 #include "pxa2xx-pcm.h"
 #include "pxa2xx-ac97.h"