proximity: vl53l0x: Make VDD regulator actually optional

proximity: vl53l0x: Make VDD regulator actually optional

Contrary to what the naming might suggest, devm_regulator_get_optional
returns -ENODEV in case the regulator is not found which will trigger
probe error in this driver.

Use devm_regulator_get instead which will return a dummy regulator that
we can just use as if it was a proper regulator.

Fixes: 7ff2e3be9c3e ("proximity: vl53l0x: Handle the VDD regulator")
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Link: https://lore.kernel.org/r/20220614112049.302278-1-luca.weiss@fairphone.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>