Add Threshold Critical Errors

Added Sensor Threshold CriticalHigh and CriticalLow errors.

Change-Id: Ie29a39ed5c58e51a38c33952e582de1b35811247
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/xyz/openbmc_project/Sensor/Threshold.errors.yaml b/xyz/openbmc_project/Sensor/Threshold.errors.yaml
new file mode 100644
index 0000000..4b8e5c0
--- /dev/null
+++ b/xyz/openbmc_project/Sensor/Threshold.errors.yaml
@@ -0,0 +1,7 @@
+# xyz.openbmc_project.Sensor.Threshold.CriticalHigh
+- name: CriticalHigh
+  description: Sensor device has exceeded its upper bound.
+
+# xyz.openbmc_project.Sensor.Threshold.CriticalLow
+- name: CriticalLow
+  description: Sensor device has exceeded its lower bound.