media: vimc.rst: add vimc-streamer source documentation

Since vimc-streamer.{c, h} are fully documented and conforming with the
kernel-doc syntax, add those files to vimc.rst
Signed-off-by: André Almeida <andrealmeid@collabora.com>
Suggested-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/media/v4l-drivers/vimc.rst

@@ -96,3 +96,14 @@ those arguments to each subdevice, not to the vimc module. For example::
         Window size to calculate the mean. Note: the window size needs to be an
         odd number, as the main pixel stays in the center of the window,
         otherwise the next odd number is considered (the default value is 3).
+
+Source code documentation
+-------------------------
+
+vimc-streamer
+~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/media/platform/vimc/vimc-streamer.h
+   :internal:
+
+.. kernel-doc:: drivers/media/platform/vimc/vimc-streamer.c