regulator: vctrl: Use locked regulator_get_voltage in probe path

In commit e9153311 ("regulator: vctrl-regulator: Avoid deadlock getting
and setting the voltage"), all calls to get/set the voltage of the
control regulator were switched to unlocked versions to avoid deadlocks.
However, the call in the probe path is done without regulator locks
held. In this case the locked version should be used.

Switch back to the locked regulator_get_voltage() in the probe path to
avoid any mishaps.

Fixes: e9153311

 ("regulator: vctrl-regulator: Avoid deadlock getting and setting the voltage")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20210825033704.3307263-2-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>