media: hi556: Support full range of power rails

Use regulator_bulk_* to get the array of potential power rails for
the hi556.

Previously the driver only supported avdd as only avdd is used on IPU6
designs. But other designs may also need the driver to control the other
power rails and the new INT3472 handshake support also makes use of
dvdd on IPU6 designs.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2368506


Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>