km/common: add printings to boardid commands

Be verbose if do_setboardid was called and print
correct names of variables in do_checkboardidhwk.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
cc: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>