dw9768: Enable low-power probe on ACPI

Add support for low-power probe to the driver. Also fix runtime PM API
usage in the driver.

Much of the hassle comes from different factors affecting device power
states during probe for ACPI and DT.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Fixes: 85989122 ("media: i2c: dw9768: Add DW9768 VCM driver")