ARM: dts: exynos4: Add stdout-path properties

This patch adds stdout-path property to chosen nodes of Exynos4 boards
to enable use of earlycon feature without the need to hardcode port
number in kernel itself.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>