drm/drm_drv.c: Remove duplicate header

Remove drm_crtc_internal.h which is included more than once

Signed-off-by: Brajeswar Ghosh <brajeswar.linux@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181224143636.GA3237@hp-pavilion-15-notebook-pc-brajeswar