seccomp: add shmctl(), mlock(), and munlock() to the syscall whitelist

Additional testing reveals that PulseAudio requires shmctl() and the
mlock()/munlock() syscalls on some systems/configurations.  As before,
on systems that do require these syscalls, the problem can be seen with
the following command line:

  # qemu -monitor stdio  -sandbox on \
         -device intel-hda -device hda-duplex

Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Eduardo Otubo <otubo@linux.vnet.ibm.com>

qemu-seccomp.c

@@ -227,7 +227,10 @@ static const struct QemuSeccompSyscall seccomp_whitelist[] = {
     { SCMP_SYS(shmget), 240 },
     { SCMP_SYS(shmat), 240 },
     { SCMP_SYS(shmdt), 240 },
-    { SCMP_SYS(timerfd_create), 240 }
+    { SCMP_SYS(timerfd_create), 240 },
+    { SCMP_SYS(shmctl), 240 },
+    { SCMP_SYS(mlock), 240 },
+    { SCMP_SYS(munlock), 240 }
 };
 
 int seccomp_start(void)