rock5b + mcp251x: Updates and device tree overlay

This PR is a response to https://github.com/Joshua-Riek/ubuntu-rockchip/issues/1054. It includes - the device tree overlay for mcp2515 on spi0-m2-cs0 [from Radxa's original (archived) repo](https://github.com/radxa/overlays/blob/56dabd510fef878cd3a1320cf8d7dcbf493b2524/arch/arm64/boot/dts/rockchip/overlays/rk3588-spi0-m2-cs0-mcp2515-8mhz.dts) - all fixes to the driver itself that are currently in the upstream master, including a fix for [CVE-2024-46791](https://lore.kernel.org/linux-cve-announce/2024091853-CVE-2024-46791-af66@gregkh/T/). Unfortunately, i was not able to test this as thoroughly as I'd like; We're still having some reliability and data integrity issues, but that might as well be a hardware issue on our side, since we were having those with the original Radxa kernel as well. However, I'm submitting it here as a PR in case anyone else needs this setup.