of: Grammar s/an/a/

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

drivers/of/base.c

@@ -933,7 +933,7 @@ const struct of_device_id *__of_match_node(const struct of_device_id *matches,
 }
 
 /**
- * of_match_node - Tell if an device_node has a matching of_match structure
+ * of_match_node - Tell if a device_node has a matching of_match structure
  *	@matches:	array of of device match structures to search in
  *	@node:		the of device structure to match against
  *