drm/i915: Pass intel_crtc to DDI functions called from crtc en/disable

Pass intel_crtc to functions intel_ddi_enable_transcoder_func(),
intel_ddi_set_pipe_settings() and intel_ddi_set_vc_payload_alloc(),
instead of the generic crtc type. By changing the functions
intel_ddi_get_crtc_encoder() so that it receives an intel_crtc
parameter, there is no need for the drm_crtc in the callers.

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170302125857.14665-6-ander.conselvan.de.oliveira@intel.com