ASoC: pcm3168a: remove numeric PCM3168A_NUM_SUPPLIES

Just use ARRAY_SIZE() instead.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Link: https://lore.kernel.org/r/20220208084220.1289836-5-nikita.yoush@cogentembedded.com


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