[PATCH] uml: fix compile error for tt

arch/um/kernel/tt/uaccess.c: In function `copy_from_user_tt':
arch/um/kernel/tt/uaccess.c:11: error: `FIXADDR_USER_START' undeclared (first use in this function)
arch/um/kernel/tt/uaccess.c:11: error: (Each undeclared identifier is reported only once
arch/um/kernel/tt/uaccess.c:11: error: for each function it appears in.)

I get the compile error when I disable CONFIG_MODE_SKAS.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paolo 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>