dt-bindings: net: Rename renesas,r9a09g057-gbeth.yaml

The DT bindings file "renesas,r9a09g057-gbeth.yaml" applies to a whole
family of SoCs, and uses "renesas,rzv2h-gbeth" as a fallback compatible
value.  Hence rename it to the more generic "renesas,rzv2h-gbeth.yaml".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/721f6e0e09777e0842ecaca4578bc50c953d2428.1750838954.git.geert+renesas@glider.be


Signed-off-by: Jakub Kicinski <kuba@kernel.org>