tools/kvm_stat: add sample systemd unit file

Add a sample unit file as a basis for systemd integration of kvm_stat
logs.
Signed-off-by: Stefan Raspl <raspl@de.ibm.com>
Message-Id: <20200402085705.61155-4-raspl@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/kvm/kvm_stat/kvm_stat.service

+# SPDX-License-Identifier: GPL-2.0-only
+
+[Unit]
+Description=Service that logs KVM kernel module trace events
+Before=qemu-kvm.service
+
+[Service]
+Type=simple
+ExecStart=/usr/bin/kvm_stat -dtcz -s 10 -L /var/log/kvm_stat.csv
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=always
+SyslogIdentifier=kvm_stat
+SyslogLevel=debug
+
+[Install]
+WantedBy=multi-user.target