ASoC: cs53l30: Correct number of volume levels on SX controls

This driver specified the maximum value rather than the number of volume
levels on the SX controls, this is incorrect, so correct them.

Reported-by: David Rhodes <david.rhodes@cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220602162119.3393857-4-ckeepax@opensource.cirrus.com


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