drm/amd/display/dc/core/dc: Convert function headers to kernel-doc

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc.c:3324: warning: Cannot understand  *****************************************************************************
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc.c:3344: warning: Cannot understand  *****************************************************************************
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc.c:3417: warning: Cannot understand  *****************************************************************************

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -3335,18 +3335,10 @@ void dc_hardware_release(struct dc *dc)
 #endif
 
 /**
- *****************************************************************************
- *  Function: dc_enable_dmub_notifications
+ * dc_enable_dmub_notifications - Returns whether dmub notification can be enabled
+ * @dc: dc structure
  *
- *  @brief
- *		Returns whether dmub notification can be enabled
- *
- *  @param
- *		[in] dc: dc structure
- *
- *	@return
- *		True to enable dmub notifications, False otherwise
- *****************************************************************************
+ * Returns: True to enable dmub notifications, False otherwise
  */
 bool dc_enable_dmub_notifications(struct dc *dc)
 {
@@ -3355,21 +3347,13 @@ bool dc_enable_dmub_notifications(struct dc *dc)
 }
 
 /**
- *****************************************************************************
- *  Function: dc_process_dmub_aux_transfer_async
- *
- *  @brief
- *		Submits aux command to dmub via inbox message
+ * dc_process_dmub_aux_transfer_async - Submits aux command to dmub via inbox message
  *                                      Sets port index appropriately for legacy DDC
+ * @dc: dc structure
+ * @link_index: link index
+ * @payload: aux payload
  *
- *  @param
- *		[in] dc: dc structure
- *		[in] link_index: link index
- *		[in] payload: aux payload
- *
- *	@return
- *		True if successful, False if failure
- *****************************************************************************
+ * Returns: True if successful, False if failure
  */
 bool dc_process_dmub_aux_transfer_async(struct dc *dc,
 				uint32_t link_index,
@@ -3428,16 +3412,8 @@ bool dc_process_dmub_aux_transfer_async(struct dc *dc,
 }
 
 /**
- *****************************************************************************
- *  Function: dc_disable_accelerated_mode
- *
- *  @brief
- *		disable accelerated mode
- *
- *  @param
- *		[in] dc: dc structure
- *
- *****************************************************************************
+ * dc_disable_accelerated_mode - disable accelerated mode
+ * @dc: dc structure
  */
 void dc_disable_accelerated_mode(struct dc *dc)
 {