dt-bindings: net: convert nxp,lpc1850-dwmac.txt to yaml format

dt-bindings: net: convert nxp,lpc1850-dwmac.txt to yaml format

Convert nxp,lpc1850-dwmac.txt to yaml format.

Additional changes:
- compatible string add fallback as "nxp,lpc1850-dwmac", "snps,dwmac-3.611"
"snps,dwmac".
- add common interrupts, interrupt-names, clocks, clock-names, resets and
  reset-names properties.
- add ref snps,dwmac.yaml.
- add phy-mode in example to avoid dt_binding_check warning.
- update examples to align lpc18xx.dtsi.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20250630161613.2838039-1-Frank.Li@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>