arm64: dts: meson: update the Khadas VIM3/3L LED bindings

Update the VIM3/3L common dtsi to use the new function/color bindings.

Suggested-by: Artem Lapkin <art@khadas.com>
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20201125052914.4092-1-christianshewitt@gmail.com