qemu: Report cache occupancy (CMT) with domstats

qemu: Report cache occupancy (CMT) with domstats

Adding the interface in qemu to report CMT statistic information
through command 'virsh domstats --cpu-total'.

Below is a typical output:

         # virsh domstats 1 --cpu-total
         Domain: 'ubuntu16.04-base'
           ...
           cpu.cache.monitor.count=2
           cpu.cache.monitor.0.name=vcpus_1
           cpu.cache.monitor.0.vcpus=1
           cpu.cache.monitor.0.bank.count=2
           cpu.cache.monitor.0.bank.0.id=0
           cpu.cache.monitor.0.bank.0.bytes=4505600
           cpu.cache.monitor.0.bank.1.id=1
           cpu.cache.monitor.0.bank.1.bytes=5586944
           cpu.cache.monitor.1.name=vcpus_4-6
           cpu.cache.monitor.1.vcpus=4,5,6
           cpu.cache.monitor.1.bank.count=2
           cpu.cache.monitor.1.bank.0.id=0
           cpu.cache.monitor.1.bank.0.bytes=17571840
           cpu.cache.monitor.1.bank.1.id=1
           cpu.cache.monitor.1.bank.1.bytes=29106176

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>