boards: riscv: add ICE-V Wireless board

The ICE-V Wireless includes an ESP32-C3, an iCE40UP5k-SG48 FPGA,
and an 8MB PSRAM connected directly to the FPGA.

This change adds initial support for the ESP32-C3 RISC-V
application processor.

For more information, please see
https://github.com/ICE-V-Wireless/ICE-V-Wireless



Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>