ARM: dts: Enable audio support for exynos5800-peach-pi

Peach-pi board has MAX98091 audio codec connected on HSI2C-7 bus.

Signed-off-by: Tushar Behera <tushar.b@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>