drm/dp: Export symbol / kerneldoc fixes for DP AUX bus

While working on the DP AUX bus code I found a few small things that
should be fixed. Namely the non-devm version of
of_dp_aux_populate_ep_devices() was missing an export. There was also
an extra blank line in a kerneldoc and a kerneldoc that incorrectly
documented a return value. Fix these.

Fixes: aeb33699 ("drm: Introduce the DP AUX bus")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510122726.v3.1.Ia91f4849adfc5eb9da1eb37ba79aa65fb3c95a0f@changeid

drivers/gpu/drm/display/drm_dp_aux_bus.c

@@ -66,7 +66,6 @@ static int dp_aux_ep_probe(struct device *dev)
  * @dev: The device to remove.
  *
  * Calls through to the endpoint driver remove.
- *
  */
 static void dp_aux_ep_remove(struct device *dev)
 {
@@ -120,8 +119,6 @@ ATTRIBUTE_GROUPS(dp_aux_ep_dev);
 /**
  * dp_aux_ep_dev_release() - Free memory for the dp_aux_ep device
  * @dev: The device to free.
- *
- * Return: 0 if no error or negative error code.
  */
 static void dp_aux_ep_dev_release(struct device *dev)
 {
@@ -256,6 +253,7 @@ int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(of_dp_aux_populate_ep_devices);
 
 static void of_dp_aux_depopulate_ep_devices_void(void *data)
 {