drm/i915: turn some bogus kernel-doc comments to normal comments

Apparently accidental or misplaced /** kernel-doc comments, confusing
the tool. Turn them to normal comments.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453101588-18008-2-git-send-email-jani.nikula@intel.com

drivers/gpu/drm/i915/intel_pm.c

@@ -4138,7 +4138,7 @@ void intel_update_watermarks(struct drm_crtc *crtc)
 		dev_priv->display.update_wm(crtc);
 }
 
-/**
+/*
  * Lock protecting IPS related data structures
  */
 DEFINE_SPINLOCK(mchdev_lock);

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -410,7 +410,7 @@ intel_write_status_page(struct intel_engine_cs *ring,
 	ring->status_page.page_addr[reg] = value;
 }
 
-/**
+/*
  * Reads a dword out of the status page, which is written to from the command
  * queue by automatic updates, MI_REPORT_HEAD, MI_STORE_DATA_INDEX, or
  * MI_STORE_DATA_IMM.