testing/mstflint: new aport

Package Mellanox Firmware Tools (mstflint) for Alpine Linux: https://github.com/Mellanox/mstflint

musl patch from: https://github.com/Mellanox/mstflint/issues/582

Only tested on x86_64 as that's the only platform I have with PCIe slots to accept the Mellanox network adapter. Added aarch64 to supported architectures as there is likely ARM64 hardware compatible with the NICs.