This patch removes unnecessary descriptions on
exynos_drm_crtc structure and adds one description
which specifies what pipe_clk member does.
pipe_clk support had been added by below patch without any description,
drm/exynos: add support for pipeline clock to the framework
Commit-id : f26b9343f5
Signed-off-by: Inki Dae <inki.dae@samsung.com>