qemu: Generate and use zPCI device in QEMU command line

Add new functions to generate zPCI command string and append it to
QEMU command line. And the related tests are added.

Signed-off-by: Yi Min Zhao <zyimin@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>

tests/qemuxml2argvdata/hostdev-vfio-zpci-autogenerate.args

@@ -0,0 +1,25 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-s390x \
+-name QEMUGuest1 \
+-S \
+-machine s390-ccw-virtio,accel=tcg,usb=off,dump-guest-core=off \
+-m 214 \
+-smp 1,sockets=1,cores=1,threads=1 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,path=/tmp/lib/domain--1-QEMUGuest1/monitor.sock,\
+server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-device zpci,uid=1,fid=0,target=hostdev0,id=zpci1 \
+-device vfio-pci,host=00:00.0,id=hostdev0,bus=pci.0,addr=0x1 \
+-device zpci,uid=2,fid=1,target=balloon0,id=zpci2 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2