usb: move ReST documentation to Documentation/driver-api/usb/

This is where all other USB ReST documentation has moved to.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Documentation/driver-api/usb/index.rst

@@ -18,6 +18,8 @@ Linux USB API
    writing_usb_driver
    dwc3
    writing_musb_glue_layer
+   typec
+   usb3-debug-port
 
 .. only::  subproject and html