USB: serial: metro-usb: Fix idProduct for Uni-Directional mode.

The right idProduct for Metrologic Bar Code Scanner
in Uni-Directional Serial Emulation mode is 0x0700.

Also rename idProduct for Bi-Directional mode to be a bit more informative.

Signed-off-by: Aleksey Babahin <tamerlan311@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>