As Michael pointed out, create_events_from_catalog() fails when we
either have:
 - a kernel bug
 - some sort of hypervisor misconfiguration
 - ENOMEM

In all the above cases, we can also fail 24x7 initcall.

For hypervisor errors, EIO is used so there is something reported
in dmesg.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>