asoc: wcd937x: move export functions to new header

For export functions from wcd937x use separate
header as internal header is only supposed to be
used within wcd937x driver logic.

Change-Id: Ice373ff95f7166a2f968458b25223c582edc7fba
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>

asoc/codecs/wcd937x/wcd937x.c

@@ -25,6 +25,7 @@
 #include <sound/soc.h>
 #include <sound/soc-dapm.h>
 #include "internal.h"
+#include "wcd937x.h"
 #include "../wcdcal-hwdep.h"
 #include "wcd937x-registers.h"
 #include "../msm-cdc-pinctrl.h"