virtio: console: Use str_yes_no() helper in port_debugfs_show()

Remove hard-coded strings by using the str_yes_no() helper function.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Amit Shah <amit@kernel.org>
Link: https://lore.kernel.org/r/20250212114841.74650-2-thorsten.blum@linux.dev


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>