kvm tools: Repair running on non ioeventfd-capable platforms

Commit d3923126a24212f1e746a84a575dadbd9f259418 added a bunch of
nice error checking around ioevent__init() but the init may gracefully
fail if ioevents simply aren't supported (PPC64 KVM).

This commit adds a new return code for the init -- positive, but
identifiable as 'not success 0'.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
1 file changed