KVM: nVMX: consult PFEC_MASK and PFEC_MATCH when generating #PF VM-exit

When generating #PF VM-exit, check equality:
(PFEC & PFEC_MASK) == PFEC_MATCH
If there is equality, the 14 bit of exception bitmap is used to take decision
about generating #PF VM-exit. If there is inequality, inverted 14 bit is used.

Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>