Fix espflash::write_bin

[Rimpampa]

I was encountering this error while using the espflash CLI utility, more specifically the write-bin subcommand:

> cargo run -p espflash -- write-bin 0x0 file.bin
[2023-02-14T08:08:28Z INFO ] Serial port: 'COM20'
[2023-02-14T08:08:28Z INFO ] Connecting...
[2023-02-14T08:08:28Z INFO ] Serial port: 'COM20'
[2023-02-14T08:08:28Z INFO ] Connecting...
Error: espflash::connection_failed

  x Failed to open serial port COM20
  |-> Failed to open serial port COM20
  |-> Error while connecting to device
  `-> Serial port not found
  help: Ensure that the device is connected and your host recognizes the serial adapter

And I found it strange that the serial port was being opened twice in a row, and by looking at the code I found the problem: board_info tries to open a new connection when a connect was already previously called.

Switching to print_board_info which reuses the same connection solved the problem

[jessebraham]

Thanks for the fix, must have missed this back when I changed this last.