drm/i915: Use plane_name() in gen7_enable_fbc()

All the other .enable_fbc() funcs use plane_name(). Make
gen7_enable_fbc() do the same.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -295,7 +295,7 @@ static void gen7_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
 
 	sandybridge_blit_fbc_update(dev);
 
-	DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);
+	DRM_DEBUG_KMS("enabled fbc on plane %c\n", plane_name(intel_crtc->plane));
 }
 
 bool intel_fbc_enabled(struct drm_device *dev)