[PATCH] uml: fix critical typo for TT mode

Noticed this for a compilation-time warning, so I'm fixing it even for TT mode
- this is not put_user, but copy_to_user, so we need a pointer to sp, not sp
itself (we're trying to write the word pointed to by the "sp" var.).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>