migration: Build migration_files once

The items in migration_files are built for libmigration and included
info softmmu_ss from there; no need to also include them directly.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed