of/overlay: Grammar s/an negative/a negative/

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/overlay.c

@@ -333,7 +333,7 @@ static DEFINE_IDR(ov_idr);
  * of the overlay in a list. This list can be used to prevent
  * illegal overlay removals.
  *
- * Returns the id of the created overlay, or an negative error number
+ * Returns the id of the created overlay, or a negative error number
  */
 int of_overlay_create(struct device_node *tree)
 {
@@ -481,7 +481,7 @@ static int overlay_removal_is_ok(struct of_overlay *ov)
  *
  * Removes an overlay if it is permissible.
  *
- * Returns 0 on success, or an negative error number
+ * Returns 0 on success, or a negative error number
  */
 int of_overlay_destroy(int id)
 {
@@ -528,7 +528,7 @@ EXPORT_SYMBOL_GPL(of_overlay_destroy);
  *
  * Removes all overlays from the system in the correct order.
  *
- * Returns 0 on success, or an negative error number
+ * Returns 0 on success, or a negative error number
  */
 int of_overlay_destroy_all(void)
 {