vdso/restorer: Simplify vdso/vvar order checking

Ordering check for vvar/vdso blobs was introduced with
the commit b00bdb2d ("vdso: x86 -- Test VMAs order in vdso_proxify")
Let's simplify it to more readable version.
As above we've compared that vvar/vdso's blob size from dumpee matches
sizes of rt-vvar/rt-vdso, kill that xor here.
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/pie/parasite-vdso.c

@@ -171,7 +171,7 @@ int vdso_proxify(struct vdso_symtable *sym_rt, unsigned long vdso_rt_parked_at,
 					long delta_rt = sym_rt->vvar_start - sym_rt->vdso_start;
 					long delta_this = vma_vvar->start - vma_vdso->start;
 
-					remap_rt = (delta_rt ^ delta_this) < 0 ? false : true;
+					remap_rt = (delta_rt == delta_this);
 				}
 			} else
 				remap_rt = true;