board_status.sh: Update to fix serial port reads

The old serial port read method lost characters from the boot log. This
method works better for me.

- Put get_serial_bootlog arguments into variable names for clarity.
- Fully configure the serial port with stty: disable parity and flow control.
- Change serial port read from reading with 'cat' to reading with 'read'.
- Update help to show current default speed from the variable.

tested under dash, bash, and zsh on several platfoms.

Change-Id: I91ae63a3c226e61019dbdf69c405c3f20ba7db54
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12757
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

0 files changed, 0 insertions, 0 deletions