drm/i915/bxt: Assign PLL for pipe

Assign PLL for pipe (dependent on port attached to the pipe)

v2:
- fix incorrect encoder vs. new_encoder check for crtc (imre)

v3:
- warn and return error if no encoder is attached (imre)

Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v2)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Don't move intel_ddi_get_crtc_new_encoder around.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_ddi.c

@@ -493,7 +493,7 @@ intel_ddi_get_crtc_encoder(struct drm_crtc *crtc)
 	return ret;
 }
 
-static struct intel_encoder *
+struct intel_encoder *
 intel_ddi_get_crtc_new_encoder(struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);