dt-bindings: arm: mediatek: move ethsys controller & convert to DT schema

DT schema helps validating DTS files. Binding was moved to clock/ as
this hardware is a clock provider. Example required a small fix for
"reg" value (1 address cell + 1 size cell).

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20231119212416.2682-1-zajec5@gmail.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>