ASoC: ml26124: remove unused variable 'ngth'

In file included from ./include/sound/tlv.h:10:0,
                 from sound/soc/codecs/ml26124.c:19:
sound/soc/codecs/ml26124.c:59:35: warning: ngth defined but not used [-Wunused-const-variable=]
 static const DECLARE_TLV_DB_SCALE(ngth, -7650, 150, 0);
                                   ^
./include/uapi/sound/tlv.h:64:15: note: in definition of macro SNDRV_CTL_TLVD_DECLARE_DB_SCALE
  unsigned int name[] = { \
               ^~~~
sound/soc/codecs/ml26124.c:59:14: note: in expansion of macro DECLARE_TLV_DB_SCALE
 static const DECLARE_TLV_DB_SCALE(ngth, -7650, 150, 0);
              ^~~~~~~~~~~~~~~~~~~~

It is never used, so can be removed.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190809082440.67412-1-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/ml26124.c

@@ -56,7 +56,6 @@ static const DECLARE_TLV_DB_SCALE(alclvl, -2250, 150, 0);
 static const DECLARE_TLV_DB_SCALE(mingain, -1200, 600, 0);
 static const DECLARE_TLV_DB_SCALE(maxgain, -675, 600, 0);
 static const DECLARE_TLV_DB_SCALE(boost_vol, -1200, 75, 0);
-static const DECLARE_TLV_DB_SCALE(ngth, -7650, 150, 0);
 
 static const char * const ml26124_companding[] = {"16bit PCM", "u-law",
 						  "A-law"};