drm: Roll out drm_for_each_{plane,crtc,encoder}

Remaining manual work in the drm core&helpers. Nothing special here,
no surprises.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

diff --cc drivers/gpu/drm/drm_crtc.c
Simple merge

diff --cc drivers/gpu/drm/drm_crtc_helper.c
Simple merge

diff --cc drivers/gpu/drm/drm_fb_cma_helper.c
Simple merge

diff --cc drivers/gpu/drm/drm_modeset_lock.c
Simple merge