While setting the KVM PIT counters in 'kvm_pit_load_count', if
'hpet_legacy_start' is set, the function disables the timer on
channel[0], instead of the respective index 'channel'. This is
because channels 1-3 are not linked to the HPET.  Fix the caller
to only activate the special HPET processing for channel 0.
Reported-by: P J P <pjp@fedoraproject.org>
Fixes: 0185604cSigned-off-by: Paolo Bonzini <pbonzini@redhat.com>