gen_nodes: add device vmcoreinfo to guestfs q35

This enables dumping the coredump of the VM in case of crash in
the kernel.

Note that CONFIG_FW_CFG_SYSFS and CONFIG_KDUMP needs to enabled.

Once the crash happens, run:
virsh dump --memory-only <vmname> ../vmcore

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>

Author: Panky-codes

playbooks/roles/gen_nodes/templates/guestfs_q35.j2.xml

@@ -183,6 +183,8 @@
     <qemu:arg value='-global'/>
     <qemu:arg value='ICH9-LPC.disable_s4=0'/>
     <qemu:arg value='-device'/>
+    <qemu:arg value='vmcoreinfo'/>
+    <qemu:arg value='-device'/>
     <qemu:arg value='pxb-pcie,id=pcie.1,bus_nr=32,bus=pcie.0,addr=0x8'/>
     {% if libvirt_enable_gdb %}
       <qemu:arg value='-gdb'/>