Documentation: kvm: fix a typo

Fixes: 9824c83f

 ("Documentation: kvm: document CPUID bit for MSR_KVM_POLL_CONTROL")
Signed-off-by: Li Qiang <liq3ea@163.com>
Link: https://lore.kernel.org/r/20201002150422.6267-1-liq3ea@163.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>