Name devices ttyUSB* instead of ttyCH343USB*

[shuyuan-liu]

I think the driver should name its devices ttyUSB* like all other USB-serial drivers do (ch341, ftdi_sio, and probably the pl2303 driver although not tested), instead of ttyCH343USB*. Three reasons are:

• This driver supports multiple chips (CH9102, CH347, …) but names all of them "CH343", which can be confusing;
• Including "CH343" in the device name is somewhat intrusive and might come off as unwelcome advertising; it's better to use the neutral, generic name ttyUSB*. If a user wants to rename a device to be more specific they could always write udev rules to do so;
• ttyCH343USB is longer and more cumbersome to type in a terminal than ttyUSB.