PEL: Update sev of critical threshold errors

The Temperature/Voltage CriticalHigh/Low PELs previously had a PEL
severity of 'predictive', and this commit changes them to
'unrecoverable' so that it matches the D-Bus severity value it's being
created with.

Note: The D-Bus severity value is 'critical'.  While there is a PEL
severity value of 'critical', both 'unrecoverable' and 'critical' get
mapped to the Redfish field value of 'Critical' anyway, and the PEL
'critical' field seems to be just used for system crashes and the like.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I174c48180abe9ddca09d0e020e6d16f81311bb61
diff --git a/extensions/openpower-pels/registry/message_registry.json b/extensions/openpower-pels/registry/message_registry.json
index 805beb4..c2bb0b2 100644
--- a/extensions/openpower-pels/registry/message_registry.json
+++ b/extensions/openpower-pels/registry/message_registry.json
@@ -5042,7 +5042,7 @@
             "Name": "xyz.openbmc_project.Sensor.Threshold.Error.TemperatureCriticalHigh",
             "Subsystem": "power",
             "ComponentID": "0x2800",
-            "Severity": "predictive",
+            "Severity": "unrecoverable",
             "ActionFlags": ["service_action", "report"],
 
             "SRC": {
@@ -5296,7 +5296,7 @@
             "Name": "xyz.openbmc_project.Sensor.Threshold.Error.VoltageCriticalLow",
             "Subsystem": "cec_tod",
             "ComponentID": "0x2800",
-            "Severity": "predictive",
+            "Severity": "unrecoverable",
             "ActionFlags": ["service_action", "report"],
 
             "SRC": {
@@ -5376,7 +5376,7 @@
             "Name": "xyz.openbmc_project.Sensor.Threshold.Error.TemperatureCriticalLow",
             "Subsystem": "power",
             "ComponentID": "0x2800",
-            "Severity": "predictive",
+            "Severity": "unrecoverable",
             "ActionFlags": ["service_action", "report"],
 
             "SRC": {