drm/i915: fix kernel-doc warnings in intel_audio.c

Fix the following 'make htmldocs' warnings:

  .//drivers/gpu/drm/i915/intel_audio.c:439: warning: No description found for parameter 'intel_encoder'
  .//drivers/gpu/drm/i915/intel_audio.c:439: warning: Excess function parameter 'encoder' description in 'intel_audio_codec_disable'
  .//drivers/gpu/drm/i915/intel_audio.c:439: warning: No description found for parameter 'intel_encoder'
  .//drivers/gpu/drm/i915/intel_audio.c:439: warning: Excess function parameter 'encoder' description in 'intel_audio_codec_disable'

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 89c1a8ce..2a5c76f 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -430,7 +430,7 @@
 
 /**
  * intel_audio_codec_disable - Disable the audio codec for HD audio
- * @encoder: encoder on which to disable audio
+ * @intel_encoder: encoder on which to disable audio
  *
  * The disable sequences must be performed before disabling the transcoder or
  * port.