bhyve: support 'isa' controller for LPC

bhyve: support 'isa' controller for LPC

Support modeling of the 'isa' controller for bhyve. User can manually
define any PCI slot for the 'isa' controller, including PCI slot 1,
but other devices are not allowed to use this address.

When domain configuration requires the 'isa' controller to be present,
automatically add it on domain post-parse stage.

Now, as this controller is always available when needed, it's not
necessary to implicitly add it to the bhyve command line, so remove
bhyveBuildLPCArgStr().

Also, make bhyveDomainDefNeedsISAController() static as it's no longer
used outside of bhyve_domain.c.

As more than one ISA controller is not supported by bhyve,
and multiple controllers with the same index are forbidden,
so forbid ISA controllers with non-zero index for bhyve.

Signed-off-by: Roman Bogorodskiy <bogorodskiy@gmail.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>