ASoC: pcm512x: Use the correct range constraints for S24_LE

This was overlooked in the late change to remove the I2S padding bits
from S24_LE mode. The patch also limits S32_LE mode to 384kHz, the
maximum according to the datasheets.

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Mark Brown <broonie@kernel.org>