It adds a crtc helper drm_crtc_from_index() to find the registered CRTC
with a given index, just like drm_plane_from_index().
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1483015290-16660-2-git-send-email-shawnguo@kernel.org