kvm: debugfs: add fastpath msr_wr exits to debugfs statistics

virt inclusion
category: feature
bugzilla: 46853
CVE: NA

At present, there is a flaw in the statistics of KVM exits by debugfs,
which only counts trigger times of exits processing function in kvm_vmx_exit_handlers.
The kvm exits handles in vmx_exit_handlers_fastpath is omitted, so there is a large numerical error
in EXIT_REASON_MSR_WRITE statistics sometimes.

Signed-off-by: chenjiajun <chenjiajun8@huawei.com>
Reviewed-by: Xiangyou Xie <xiexiangyou@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>