seccomp: add riscv_hwprobe to @default

This syscall is for probing hardware capabilities from userspace and should do no harm.
Added in ea3de9ce8a

src/shared/seccomp-util.c

@@ -358,6 +358,7 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 "prlimit64\0"
                 "restart_syscall\0"
                 "riscv_flush_icache\0"
+                "riscv_hwprobe\0"
                 "rseq\0"
                 "rt_sigreturn\0"
                 "sched_getaffinity\0"