regulator: tps6594-regulator: remove hardcoded buck config

regulator: tps6594-regulator: remove hardcoded buck config

Commit 00c826525fba ("regulator: tps6594-regulator: Add TI TPS65224 PMIC
regulators") added support for the TPS65224 and made the description of
the multi-phase buck converter variable depending on the variant of the
PMIC. But this was just done for MUTLI_BUCK12 and MULTI_BUCK12_34
configs probably because this variant only supports a multi-phase
configuration on buck 1 and 2. Remove the hardcoded value for the
remaining two configs, too as future PMIC variants might also support
these.

This is a preparation patch to refactor the regulator description and
is compile-time only tested.

Signed-off-by: Michael Walle <mwalle@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://patch.msgid.link/20250703113153.2447110-7-mwalle@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>