drivers: usb_c: numaker: support Nuvoton's M2L31 series

1. Support USB-C drivers TCPC, PPC, and VBUS with UTCPD H/W IP
2. UTCPD is interconnected with Timer-triggered EADC for updating
   VBUS/VCONN voltage periodically

Signed-off-by: Chun-Chieh Li <ccli8@nuvoton.com>