gfs2: List traversal in do_promote is safe

In do_promote(), we're never removing the current entry from the list
and so the list traversal is actually safe.  Switch back to
list_for_each_entry().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/glock.c

@@ -534,11 +534,11 @@ done:
 
 static int do_promote(struct gfs2_glock *gl)
 {
-	struct gfs2_holder *gh, *tmp, *current_gh;
+	struct gfs2_holder *gh, *current_gh;
 	bool incompat_holders_demoted = false;
 
 	current_gh = find_first_strong_holder(gl);
-	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
+	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 			continue;
 		if (!may_grant(gl, current_gh, gh)) {