Add sound node and the clock configurations for the I2S controller
for audio support on the Exynos5250 SoC Arndale boards with
WM1811 based audio daughter board.

We need to increase drive strength of the I2S bus, otherwise
the audio CODEC doesn't work. Likely the CODEC's master clock
is the main issue here.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>