ASoC: SOF: fix compilation issue with readb/writeb helpers

Replace them with read8/write8 to avoid compilation issue on ARM. In
hindsight this is more consistent with the read64/write64 helpers
already used in SOF.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/alsa-devel/Y1rTFrohLqaiZAy%2F@dev-arch.thelio-3990X/


Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20221031195340.249868-1-pierre-louis.bossart@linux.intel.com


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