drm/doc: Improve ioctl/fops docs a bit more

I spotted a markup issue, plus adding the descriptions in drm_driver.
Plus a few more links while at it.

I'm still mildly unhappy with the split between fops and ioctls, but I
still think having the ioctls in the uapi chapter makes more sense. Oh
well ...

v2: Rebase.

v3: Move misplace hunk to the right patch.

Cc: Stefan Agner <stefan@agner.ch>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170531092045.3950-1-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index aa49a22..3a36b37 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -683,7 +683,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
  * 
  * DRM driver private IOCTL must be in the range from DRM_COMMAND_BASE to
  * DRM_COMMAND_END. Finally you need an array of &struct drm_ioctl_desc to wire
- * up the handlers and set the access rights:
+ * up the handlers and set the access rights::
  *
  *     static const struct drm_ioctl_desc my_driver_ioctls[] = {
  *         DRM_IOCTL_DEF_DRV(MY_DRIVER_OPERATION, my_driver_operation,
@@ -692,6 +692,9 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
  *
  * And then assign this to the &drm_driver.ioctls field in your driver
  * structure.
+ *
+ * See the separate chapter on :ref:`file operations<drm_driver_fops>` for how
+ * the driver-specific IOCTLs are wired up.
  */
 
 /**