constify dentry_operations: rest

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 0e49975..5c0f408 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -2196,7 +2196,7 @@
 	return 1;
 }
 
-static struct dentry_operations pfmfs_dentry_operations = {
+static const struct dentry_operations pfmfs_dentry_operations = {
 	.d_delete = pfmfs_delete_dentry,
 };