media: dt-bindings: ovti,ov2680: Fix the power supply names

The original .txt bindings had the OV2680 power supply names correct,
but the transition from .txt to yaml spelled them incorrectly.

Fix the OV2680 power supply names as the original .txt bindings
as these are the names used by the OV2680 driver and in devicetree.

Fixes: 57226cd8 ("media: dt-bindings: ov2680: convert bindings to yaml")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>