constify touch_atime()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/inode.c b/fs/inode.c
index d6dfb09..93a0625 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1525,7 +1525,7 @@
  *	This function automatically handles read only file systems and media,
  *	as well as the "noatime" flag and inode specific "noatime" markers.
  */
-void touch_atime(struct path *path)
+void touch_atime(const struct path *path)
 {
 	struct vfsmount *mnt = path->mnt;
 	struct inode *inode = path->dentry->d_inode;