platform/x86: int3472: For mt9m114 sensors map powerdown to powerenable

platform/x86: int3472: For mt9m114 sensors map powerdown to powerenable

mt9m114 atomisp designs declare both reset and powerdown pins in their
GPIO type DSM, but the mt9m114 only has a reset pin. The powerdown pin
seems to control the regulators suppyling power to the sensor and
the privacy LED.

Add a mapping of powerdown to powerenable for the mt9m114 for this.

While at is also add a comment to document the ov7251 mapping.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20250507184737.154747-6-hdegoede@redhat.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>