openrisc: dts: or1ksim: Add stdout-path

During reviews of the OpenRISC SMP patch series it was suggested to add
stdout-path to the SMP dts file.  Add stdout-path to our other dts files
to be a good example.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>