drivers: gpu: drm: i915L intel_lpe_audio: Fix kerneldoc comments

Add description for existing parameter 'pipe' to fix the build
warning: ./drivers/gpu/drm/i915/intel_lpe_audio.c:342: warning: No
description found for parameter 'pipe'.
Signed-off-by: Tamara Diaconita <diaconita.tamara@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170330115510.14054-1-diaconita.tamara@gmail.com

drivers/gpu/drm/i915/intel_lpe_audio.c

@@ -331,6 +331,7 @@ void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
  * audio driver and i915
  * @dev_priv: the i915 drm device private data
  * @eld : ELD data
+ * @pipe: pipe id
  * @port: port id
  * @tmds_clk_speed: tmds clock frequency in Hz
  *