hmi: Fix clearing HMER on debug trigger
hmi: Fix clearing HMER on debug trigger

In the recent patch:
  eddff9bf40 hmi: Clear unknown debug trigger

I rebased the code from an older skiboot before the HMI rework. When I
did this, I missed the handled flag. Without this the HMER is not
cleared properly and the HMI keeps happening.

This properly sets the handled flag and hence clears the HMER bit.

Signed-off-by: Michael Neuling <7b0ab45a730e48a69239010b5b8fe5fa4e8eaac6@neuling.org>
Reviewed-by: Mahesh Salgaonkar <6a890e1065a1d4e8df9dcf1d9a2c9c740bbcf8aa@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.ibm.com>

open-power/skiboot,open-power/skiboot,qemu/skiboot,shenki/skiboot,legoater/skiboot,stewart-ibm/skiboot,legoater/skiboot,qemu/skiboot,open-power/skiboot,stewart-ibm/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,qemu/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,stewart-ibm/skiboot