media: dt-bindings: vendor-prefixes: Add SK Hynix Inc.

SK Hynix built the already supported hi556 sensor (and probably much
more). For more information, see https://www.skhynix.com/



Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>