sparc64: Fix comment type in NG4 copy from user.

Noticed by Greg Onufer.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/lib/NG4copy_from_user.S

@@ -1,4 +1,4 @@
-/* NG4copy_from_user.S: Niagara-2 optimized copy from userspace.
+/* NG4copy_from_user.S: Niagara-4 optimized copy from userspace.
  *
  * Copyright (C) 2012 David S. Miller (davem@davemloft.net)
  */