uboot-phytec

image: push default arch values to arch headers

This pushes the ugly duplicated arch ifdef lists we maintain in various
image related files out to the arch headers themselves.

Acked-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Tested-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>