pc_sysfw: Pass PCMachineState to pc_system_firmware_init()

pc_sysfw: Pass PCMachineState to pc_system_firmware_init()

pc_system_firmware_init() parameter @isapc_ram_fw is PCMachineState
member pci_enabled negated.  The next commit will need more of
PCMachineState.  To prepare for that, pass a PCMachineState *, and
drop the now redundant parameter @isapc_ram_fw.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190308131445.17502-11-armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>