KVM: nVMX: Return -EINVAL when signaling failure in VM-Entry helpers

Most, but not all, helpers that are related to emulating consistency
checks for nested VM-Entry return -EINVAL when a check fails.  Convert
the holdouts to have consistency throughout and to make it clear that
the functions are signaling pass/fail as opposed to "resume guest" vs.
"exit to userspace".

Opportunistically fix bad indentation in nested_vmx_check_guest_state().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>