KVM: MMU: update comment on the number of page role combinations

Fix the number of bits in the role, and simplify the explanation of
why several bits or combinations of bits are redundant.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2021-11-16 05:11:10 -05:00
commit dc1ce45575