media: docs: uAPI: Expand error documentation for invalid 'which' value

Multiple subdev ioctls that take a 'which' field do not document the
error returned when the field has an invalid value. Expand the
documentation to fix this.

Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>

Author: pinchartl

Documentation/userspace-api/media/v4l/vidioc-subdev-enum-frame-interval.rst

@@ -107,8 +107,7 @@ appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
 
 EINVAL
-    The struct
-    :c:type:`v4l2_subdev_frame_interval_enum`
-    ``pad`` references a non-existing pad, one of the ``code``,
-    ``width`` or ``height`` fields are invalid for the given pad or the
-    ``index`` field is out of bounds.
+    The struct :c:type:`v4l2_subdev_frame_interval_enum` ``pad`` references a
+    non-existing pad, the ``which`` field has an unsupported value, one of the
+    ``code``, ``width`` or ``height`` fields are invalid for the given pad, or
+    the ``index`` field is out of bounds.

Documentation/userspace-api/media/v4l/vidioc-subdev-enum-frame-size.rst

@@ -126,7 +126,6 @@ appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
 
 EINVAL
-    The struct
-    :c:type:`v4l2_subdev_frame_size_enum`
-    ``pad`` references a non-existing pad, the ``code`` is invalid for
-    the given pad or the ``index`` field is out of bounds.
+    The struct :c:type:`v4l2_subdev_frame_size_enum` ``pad`` references a
+    non-existing pad, the ``which`` field has an unsupported value, the ``code``
+    is invalid for the given pad, or the ``index`` field is out of bounds.

Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst

@@ -158,7 +158,6 @@ appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
 
 EINVAL
-    The struct
-    :c:type:`v4l2_subdev_mbus_code_enum`
-    ``pad`` references a non-existing pad, or the ``index`` field is out
-    of bounds.
+    The struct :c:type:`v4l2_subdev_mbus_code_enum` ``pad`` references a
+    non-existing pad, the ``which`` field has an unsupported value, or the
+    ``index`` field is out of bounds.

Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst

@@ -140,8 +140,9 @@ ENOSPC
    all the available routes the subdevice exposes.
 
 EINVAL
-   The sink or source pad identifiers reference a non-existing pad, or reference
-   pads of different types (ie. the sink_pad identifiers refers to a source pad).
+   The sink or source pad identifiers reference a non-existing pad or reference
+   pads of different types (ie. the sink_pad identifiers refers to a source
+   pad), or the ``which`` field has an unsupported value.
 
 E2BIG
    The application provided ``num_routes`` for ``VIDIOC_SUBDEV_S_ROUTING`` is