KVM: x86: cleanup kvm_apic_match_*()

The majority of this patch turns
  result = 0; if (CODE) result = 1; return result;
into
  return CODE;
because we return bool now.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>