[PATCH] uml: skas0-hold-own-ldt fixups for x86-64

In a recent fixup i386 code was copied raw to x86_64 subarch to make it
compile again.

Here there are some little fixups and resyncs needed for it (mainly for
cleanliness sake) - I did an audit and found the rest of the code to be safe.

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>