kvm: x86: remove efer_reload entry in kvm_vcpu_stat

The efer_reload is never used since
commit 26bb0981 ("KVM: VMX: Use shared msr infrastructure"),
so remove it.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>