Fully Porting NuttX to the Raspberry Pi 4B

This proposal aims to complete major porting work of the NuttX RTOS to the Raspberry Pi 4B in order to vastly improve its stability and support. The goal is to attract new users with a flagship hobbyist device, showcase NuttX's ability to scale to large, 64-bit SoCs and also break NuttX into new markets with a more powerful platform (high RAM size, 64-bit architecture & 4-core SoC for applications like robotics). The milestones/deliverables for this project are: - Stabilization of existing support (I2C, EMMC, HDMI quirks) - SMP support - Full UART interface support (PL011) - Networking support (Ethernet OR WiFi) - Audio output - User demos (DOOM, LVGL dashboard, telnet)