this will allow to have no console support

Use full for bootstrap as we can save 6.5 KiB (barebox.bin) and
3.8 KiB (zbarebox.bin lzo) on at91sam9263 as example vs console simple

As on bootstrap we have often very limited size.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>