drm/i915: s/int plane/int color_plane/

To reduce the confusion between a drm plane and the planes of
framebuffers let's desiginate the latter as "color plane".
Weak-Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180907152413.15761-8-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_drv.h

@@ -1446,7 +1446,7 @@ void icl_unmap_plls_to_ports(struct drm_crtc *crtc,
 			     struct drm_atomic_state *old_state);
 
 unsigned int intel_fb_align_height(const struct drm_framebuffer *fb,
-				   int plane, unsigned int height);
+				   int color_plane, unsigned int height);
 
 /* intel_audio.c */
 void intel_init_audio_hooks(struct drm_i915_private *dev_priv);