In QEMU the kernel is loaded at the ${kernel_addr_r} address and we need
to use booti instead of bootm.

Booting the kernel works, but by manually specifying the address.

Add VisionFive 2

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:matthewcroughan/nixpkgs/6fd612ce3a656b1bcf5a1222c63294dcfcbb5361' (2022-07-08)
  → 'github:matthewcroughan/nixpkgs/39a827f18b870afb02f6c0f09151c69f2d8e7a4d' (2022-07-12)
• Updated input 'vendor-kernel':
    'github:starfive-tech/linux/943858df470556d0b7f3b31fcc10931603f0f3cc' (2022-07-05)
  → 'github:starfive-tech/linux/74003f14f92e3c8eb31536b599c1f0c7aba3cdf2' (2022-07-11)