ARM: dts: meson8b: odroidc1: add stdout-path property

To use the "earlycon" kernel command line parameter (without arguments)
we need a stdout-path property under the /chosen node. Add this to make
it easier to spot errors early in the boot process when looking for
them.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>