ARM stashes bootstage data to a known memory location before booting, so the kernel can pick it up. Add this to bootm_final() so all architectures benefit from it. The bootstage_stash_default() function is a no-op when bootstage or stashing is disabled. Signed-off-by: Simon Glass <simon.glass@canonical.com> Reviewed-by: Tom Rini <trini@konsulko.com>