Revert "drm/i915: Disable 12bpc hdmi for now"

HDMI 12bpc should be working fine now. Let it loose.

This reverts commit 5e3daaca.

v2: Rebased due to CHV/BXT port clock check improvemnts
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-and-tested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1287,8 +1287,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
 	 */
 	if (pipe_config->pipe_bpp > 8*3 && pipe_config->has_hdmi_sink &&
 	    hdmi_port_clock_valid(intel_hdmi, clock_12bpc, false) == MODE_OK &&
-	    hdmi_12bpc_possible(pipe_config) &&
-	    0 /* FIXME 12bpc support totally broken */) {
+	    hdmi_12bpc_possible(pipe_config)) {
 		DRM_DEBUG_KMS("picking bpc to 12 for HDMI output\n");
 		desired_bpp = 12*3;