PBL: console: Make independent of DEBUG_LL ...

With more stuff being done in PBL regular console support gets more and more
useful. This makes the PBL console independent of DEBUG_LL which is only
meant for early debugging but not regular output.
To use the regular PBL console a board must call pbl_set_putc() which stores
a pointer to the putc function to be used.

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

pbl: Add support for memory_display ...

The PBL has console support now, so add memory_display support aswell
which can be a good debugging aid.

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

Add PBL console support ...

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>