The riscv64 assembler carried fourteen hand-picked CSR names where the
toolchain resolves three hundred and twenty-nine: a CSRR/CSRW family
instruction naming any privileged register beyond the few base ones came
out as unknown CSR. The table now carries the RISC-V privileged
specification's register set exactly as go tool asm spells it, and a
differential test assembles every name through both assemblers and
requires the words to agree byte for byte.
Assisted-by: GLM 5.3 Flash
