Add help and a comment about the serial IO port selection to give the
user better feedback when a port index is selected.
Change-Id: I4c1614be51aee0286308fbc5c24554e218120bf7
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: http://review.coreboot.org/12487
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
ac76ed9998