riscv64 architecture images

[kallisti5]

Feature Request

riscv64 is becoming a larger player in the sbc space. Talos offering riscv64 architecture bases would open several new low-power devices to the Talos ecosystem.

A good example board is the StarFive VisionFive 2 which can have up to 8GiB of ram.

Description

riscv64gc would be the most "generic" extensions to target that would work on the most devices such as the SiFive Unleashed, SiFive Unmatched, and StarFive VisionFive 2

"If Haiku can offer riscv64 images, why can't Talos?" :-)