drm/exynos: Remove tracking log functions

This patch removes tracking log functions which were used to debug
in the early development stage and are not so important as were.
So remove them for code clean up.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>