media: docs: Deprecate mfc display delay controls

Deprecate mfc private display delay and display enable controls for
new clients and use the standard controls instead.
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst

@@ -2158,6 +2158,11 @@ MFC 5.1 Control IDs
     feature can be used for example for generating thumbnails of videos.
     Applicable to the H264 decoder.
 
+    .. note::
+
+       This control is deprecated. Use the standard
+       ``V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY_ENABLE`` control instead.
+
 ``V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY (integer)``
     Display delay value for H264 decoder. The decoder is forced to
     return a decoded frame after the set 'display delay' number of
@@ -2165,6 +2170,11 @@ MFC 5.1 Control IDs
     of display order, in addition the hardware may still be using the
     returned buffer as a reference picture for subsequent frames.
 
+    .. note::
+
+       This control is deprecated. Use the standard
+       ``V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY`` control instead.
+
 ``V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P (integer)``
     The number of reference pictures used for encoding a P picture.
     Applicable to the H264 encoder.