latest

jtag/drivers: Add general support for CH347 based interfaces

I found that there is no support for CH347 based JTAG adapters.
A WCH CH347T chip in mode 3 has one UART and one JTAG interface.
Like an FTDI FT2232 chip, you can use the CH347T chip for UART and JTAG.
With this change I add support for CH347T based JTAG adapters.
The WCH datasheet mention also a CH347F chip which wasn't available
for testing. So, this driver is only tested for CH347T chip.
The ch347 driver source code is adopted from
https://github.com/WCHSoftGroup/ch347
I've done some bug fixing in the ch347 driver code to get it working
and applied the openocd style guide to it. Finally I've added the new
ch347 driver in the build files.
I found the USB packet format by looking at public available
source code at GitHub and I've documented here:
https://www.easydevkits.com/wch-ch347-jtag-interface/

Change-Id: I5fca9dd015111e4410fea029611fdeedbb228fdb
Signed-off-by: EasyDevKits <info@easydevkits.com>