drm: exynos: use vblank hooks in struct drm_crtc_funcs

The vblank hooks in struct drm_driver are deprecated and only meant for
legacy drivers.  For modern drivers with DRIVER_MODESET flag, the hooks
in struct drm_crtc_funcs should be used instead.

As the result, exynos_drm_crtc_enable[disable]_vblank() become static
functions.  They are moved around a bit to save forward declaration
though.  Also while at it, we move one step further to kill
exynos_drm_crtc_from_pipe() completely by updating hdmi_bind() a bit.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Inki Dae <inki.dae@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1486458995-31018-9-git-send-email-shawnguo@kernel.org