qemu: Remove ATTRIBUTE_UNUSED from 'qemuCaps' of virQEMUCapsInitQMPMonitorTCG

It's actually used.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

src/qemu/qemu_capabilities.c

@@ -4389,7 +4389,7 @@ virQEMUCapsInitQMPMonitor(virQEMUCapsPtr qemuCaps,
 
 
 int
-virQEMUCapsInitQMPMonitorTCG(virQEMUCapsPtr qemuCaps ATTRIBUTE_UNUSED,
+virQEMUCapsInitQMPMonitorTCG(virQEMUCapsPtr qemuCaps,
                              qemuMonitorPtr mon)
 {
     int ret = -1;