Fixes are:
- The baudrate argument is a keyword arg, it was passed before as a
positional arg.
- Use the port and baudrate arguments passed from higher level code instead
of the hard-coded port ID and baudrate, which would allow HCI drivers to
change baudrates.
- Increase UART char timeout and RX buffer size.
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>