ASoC: simple-card-utils: remove asoc_simple_convert_fixup()

No one is using asoc_simple_convert_fixup(), we don't need to
export its symbol. This patch removes it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/874jvj8ftp.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>