In case a regulator DT node contains regulator-always-on or regulator-boot-on
property, make sure the regulator gets correctly configured by U-Boot on start
up. Unconditionally probe such regulator drivers. This is a preparatory patch
for introduction of .regulator_post_probe() which would trigger the regulator
configuration.

Parsing of regulator-always-on and regulator-boot-on DT property has been
moved to regulator_post_bind() as the information is required early, the
rest of the DT parsing has been kept in regulator_pre_probe() to avoid
slowing down the boot process.

Signed-off-by: Marek Vasut <marex@denx.de>