Backport request for ce4f78f1b53d ("riscv: signal: handle syscall restart before get_signal")

Hey Greg,

Could you please backport commit ce4f78f1b53d3327fbd32764aa333bf05fb68818 "riscv: signal: handle syscall restart before get_signal" to at least 6.6? Apparently it fixes CRIU and ptrace, but was unfortunately not given a fixes tag so I do not know how far back it is actually required. It cherry-picks to 6.1 and builds there, but I have not tested it.

Thanks, Conor.