ASoC: mediatek: mt8365: remove unused mt8365_i2s_hd_str

ASoC: mediatek: mt8365: remove unused mt8365_i2s_hd_str

The mt8365_i2s_enum and mt8365_i2s_hd_str variables are not
used anywhere, but cause a warning when building with C=1
or when enabling -Wunused-const-variable:

sound/soc/mediatek/mt8365/mt8365-dai-i2s.c:781:27: error: 'mt8365_i2s_hd_str' defined but not used [-Werror=unused-const-variable=]
  781 | static const char * const mt8365_i2s_hd_str[] = {
      |                           ^~~~~~~~~~~~~~~~~

Remove these for the moment, they can be added back if a
user comes up.

Fixes: 402bbb13a195 ("ASoC: mediatek: mt8365: Add I2S DAI support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://patch.msgid.link/20240907200053.3027553-1-arnd@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>