dt-bindings: net: sff,sfp: rename example dt nodes to be more generic

Rename the dt nodes shown in the sff,sfp.yaml examples so that they are
generic and not really tied to a specific platform.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>