KVM: arm64: Enable PV qspinlock

virt inclusion
category: feature
bugzilla: 47624
CVE: NA

--------------------------------

Linux kernel builds were run in KVM guest on HiSilicon Kunpeng920 system.
VM guests were set up with 32, 48 and 64 vCPUs on the 32 physical CPUs.
The kernel build (make -j<n>) was done in a VM with unpinned vCPUs 3
times with the best time selected and <n> is the number of vCPUs
available. The build times of the original linux 4.19.87, pvqspinlock
with various number of vCPUs are as follows:

  Kernel        32 vCPUs    48 vCPUs    60 vCPUs
  ----------    --------    --------    --------
  4.19.87       342.336s    602.048s    950.340s
  pvqsinlock    341.366s    376.135s    437.037s

Signed-off-by: Zengruan Ye <yezengruan@huawei.com>
Reviewed-by: Zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>