[PATCH] uml: obvious compile fixes for x86-64 Subarch and x86 regression fixes

This patch does some totally trivial compilation fixes.  It also restores the
debugregs manipulation, which was commented out simply because it doesn't
compile on x86_64 (we haven't yet implemented there debugregs handling).

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