dt-bindings: arm: Move MX8Menlo board to i.MX8M Mini Toradex Verdin SoM entry

The MX8Menlo board is based on i.MX8M Mini Toradex Verdin SoM
which results in compatible string in the form:
"vendor,custom-board", "toradex,som-nonwifi", "toradex,som", "fsl,soc"
Move the binding entry so this quadruplet can be matched on.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>