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/internal.h

@@ -168,6 +168,4 @@ extern int wcd937x_mbhc_micb_adjust_voltage(struct snd_soc_codec *codec,
 extern int wcd937x_get_micb_vout_ctl_val(u32 micb_mv);
 extern int wcd937x_micbias_control(struct snd_soc_codec *codec, int micb_num,
 			int req, bool is_dapm);
-extern int wcd937x_info_create_codec_entry(struct snd_info_entry *codec_root,
-				    struct snd_soc_codec *codec);
 #endif