KVM: nSVM: remove nonsensical EXITINFO1 adjustment on nested NPF

The "if" that drops the present bit from the page structure fauls makes no sense.
It was added by yours truly in order to be bug-compatible with pre-existing code
and in order to make the tests pass; however, the tests are wrong.  The behavior
after this patch matches bare metal.

Reported-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>