regulator: palmas: Fix SMPS enable/disable/is_enabled

We use regmap regulator ops to enable/disable and check if regulator
is enabled for various SMPS. However, these depend on valid
enable_reg, enable_mask and enable_value in regulator descriptor.

Currently we do not populate these for SMPS other than SMPS10, this
results in spurious results as regmap assumes that the values are
valid and ends up reading register 0x0 RTC:SECONDS_REG on Palmas
variants that do have RTC! To fix this, we update proper parameters
for the descriptor fields.

Further, we want to ensure the behavior consistent with logic
prior to commit dbabd624, where, once you do a set_mode,
enable/disable ensure the logic remains consistent and configures
Palmas to the configuration that we set with set_mode (since the
configuration register is common). To do this, we can rely on the
regulator core's regulator_register behavior where the regulator
descriptor pointer provided by the regulator driver is stored. (no
reallocation and copy is done). This lets us update the enable_value
post registration, to remain consistent with the mode we configure as
part of set_mode.

Fixes: dbabd624 ("regulator: palmas: Reemove open coded functions with helper functions")
Reported-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>