nfp: shorten CPP core probe logs

We currently print reserved BAR mappings info as we create them.
This makes the probe logs longer than necessary.  Print into a
buffer instead and log all the info as a single line.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>