platforms: add Pine64 Star64

[Ivan-Velickovic]

For once all the Star64 PRs are merged.

[Ivan-Velickovic]

Not sure what march does exactly here, march: rv64gcb would be more accurate for the Star64. The only use of march I can see is here

ci-actions/seL4-platforms/platforms.py

Lines 183 to 192 in 607634d

	def getISA(self, mode: int) -> str:
	"""Return the ISA for this platform"""
	if self.arch == "x86":
	return {32: "IA32", 64: "x86_64"}[mode]
	if self.arch == "riscv":
	return {32: "RC32IMAC", 64: "RV64IMAC"}[mode]
	return self.march.capitalize()

, where it seems to be ignoring march anyways.

[lsf37]

I might be wrong, but I think the only remaining use of march is for grouping in CI matrices. We could try to eliminate it and see what happens..

[lsf37]

👍 Happy for you to merge once the other PRs are done.

(Ok to ignore the devscript link failure for this PR)