This adds simple console support to the PBL which makes it
possible to print more complex messages in the PBL than just
strings or hex numbers. For now puts_ll is used to print the
messages, so it depends on CONFIG_DEBUG_LL which makes it
more a debugging option. However, this could be extended later
to get regular output from the PBL if desired.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>