trivial: fix an -> a typos in documentation and comments

It is always "an" if there is a vowel _spoken_ (not written).
So it is:
"an hour" (spoken vowel)
but
"a uniform" (spoken 'j')

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/acpi/utilities/utobject.c b/drivers/acpi/utilities/utobject.c
index c354e7a..4bef3cf 100644
--- a/drivers/acpi/utilities/utobject.c
+++ b/drivers/acpi/utilities/utobject.c
@@ -297,7 +297,7 @@
  *
  * RETURN:      TRUE if object is valid, FALSE otherwise
  *
- * DESCRIPTION: Validate a pointer to be an union acpi_operand_object
+ * DESCRIPTION: Validate a pointer to be a union acpi_operand_object
  *
  ******************************************************************************/
 
@@ -389,7 +389,7 @@
 {
 	ACPI_FUNCTION_TRACE_PTR(ut_delete_object_desc, object);
 
-	/* Object must be an union acpi_operand_object    */
+	/* Object must be a union acpi_operand_object    */
 
 	if (ACPI_GET_DESCRIPTOR_TYPE(object) != ACPI_DESC_TYPE_OPERAND) {
 		ACPI_ERROR((AE_INFO,