ARM: dts: Add sound node for exynos5420-peach-pit board

The audio setup on Peach-pit board is similar to Snow board, hence the
sound-card driver used on Snow board can be reused on Peach-pit board.

Peach-pit board uses MAX98090 audio codec.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>