No need for xen_vcpu_init anymore:

- the RTC emulator doesn't have any periodic timers continuously running
even in absence of guest interactions anymore;

- qemu_dummy_start_vcpu takes care of disabling TCG for us, so we don't
need to do it manually here.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NAndreas Färber <afaerber@suse.de>