KVM: X86: Lower the default timer frequency limit to 200us

KVM: X86: Lower the default timer frequency limit to 200us

Anthoine reported:
 The period used by Windows change over time but it can be 1
 milliseconds or less. I saw the limit_periodic_timer_frequency
 print so 500 microseconds is sometimes reached.

As suggested by Paolo, lower the default timer frequency limit to a
smaller interval of 200 us (5000 Hz) to leave some headroom. This
is required due to Windows 10 changing the scheduler tick limit
from 1024 Hz to 2048 Hz.

Reported-by: Anthoine Bourgeois <[email protected]>
Suggested-by: Paolo Bonzini <[email protected]>
Reviewed-by: Darren Kenny <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Radim Krčmář <[email protected]>
Cc: Anthoine Bourgeois <[email protected]>
Cc: Darren Kenny <[email protected]>
Cc: Jan Kiszka <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>