drm: tegra: use vblank hooks in struct drm_crtc_funcs

drm: tegra: 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, the wrapper functions tegra_drm_xxx get killed
completely, and tegra_dc_xxx are filled into struct drm_crtc_funcs as
vblank hooks directly.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1486458995-31018-21-git-send-email-shawnguo@kernel.org