[PATCH] uml: make tt mode-dependent options depend on MODE_TT

This makes some of the tt-specific options actually depend on CONFIG_MODE_TT.

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