ARM: dts: exynos4412-trats2: set display clock correctly

ARM: dts: exynos4412-trats2: set display clock correctly

This patch sets display clock correctly.

If Display clock isn't set correctly then you would find below messages
and Display controller doesn't work correctly since a patch[1]

   exynos-drm: No connectors reported connected with modes
   [drm] Cannot find any crtc or sizes - going 1024x768

[1] commit abc0b1447d49 ("drm: Perform basic sanity checks on probed modes")

Change-Id: I603afb80a27e4ca7cb8c8bb38b968c82309e1559
Signed-off-by: Inki Dae <inki.dae@samsung.com>