seccomp: allow sendto for vfio_user devices

as of rust 1.90, writes to unix sockets use the sendto syscall. This
affects the vcpu threads when vfio_user devices are accessed.

Signed-off-by: Stefan Nürnberger <stefan.nuernberger@cyberus-technology.de>

vmm/src/seccomp_filters.rs

@@ -810,6 +810,7 @@ fn vcpu_thread_rules(
         (libc::SYS_rt_sigreturn, vec![]),
         (libc::SYS_sched_yield, vec![]),
         (libc::SYS_sendmsg, vec![]),
+        (libc::SYS_sendto, vec![]),
         (libc::SYS_shutdown, vec![]),
         (libc::SYS_sigaltstack, vec![]),
         (libc::SYS_tgkill, vec![]),