ASoC: mediatek: mt8188-mt6359: Use bitfield macros for registers

Replace open coded instances of FIELD_GET() with it, move register
definitions at the top of the file and also replace magic numbers
with register definitions.

While at it, also change a regmap_update_bits() call to regmap_write()
because the top 29 bits of AUD_TOP_CFG (31:3) are reserved (unused).

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20230608084727.74403-6-angelogioacchino.delregno@collabora.com


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