media: dt-bindings: mipi,ccs: Don't mention vana voltage

It was mentioned vana voltage is typically 2,8 volts. This is truly sensor
dependent, and nowadays 2,8 volts is a lot.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>