ASoC: max98396: Fix TDM mode BSEL settings

In TDM mode, the BSEL register value must be set according to table 5 in the
datasheet. This patch adds a lookup function and uses it in
max98396_dai_tdm_slot().

As the first 3 entries can also be used for non-TDM setups, the code re-uses
the same table for such scenarios.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Link: https://lore.kernel.org/r/20220629050630.2848317-1-daniel@zonque.org
Signed-off-by: Mark Brown <broonie@kernel.org>