target: Delete incorrect comment

aptpl_file_mutex seems to no longer exist.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 26c1f2d..c157b3f 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -1927,9 +1927,6 @@
 	return ret;
 }
 
-/*
- * Called with struct se_device->aptpl_file_mutex held
- */
 static int __core_scsi3_write_aptpl_to_file(
 	struct se_device *dev,
 	unsigned char *buf)