state-set: Add the enum for Operational Stress Status state

As per the spec DSP0249 the PLDM state set Operational Stress Status
[Set ID: 9] can have two enumeration values defined. This commit
adds the enum for the same.

Change-Id: I37962d53c8baf48d0af7beb5ea891c0d2350f4c2
Signed-off-by: Pavithra Barithaya <pavithra.b@ibm.com>
diff --git a/include/libpldm/state_set.h b/include/libpldm/state_set.h
index 38f5aa1..0e5061c 100644
--- a/include/libpldm/state_set.h
+++ b/include/libpldm/state_set.h
@@ -156,6 +156,13 @@
 	PLDM_STATE_SET_OPERATIONAL_FAULT_STATUS_STRESSED = 2,
 };
 
+/* @brief List of states for the Operational Stress status (ID 9).
+ */
+enum pldm_state_set_operational_stress_status_values {
+	PLDM_STATE_SET_OPERATIONAL_STRESS_STATUS_NORMAL = 1,
+	PLDM_STATE_SET_OPERATIONAL_STRESS_STATUS_STRESSED = 2,
+};
+
 /* @brief List of states for the Operational Running Status state set (ID 11).
  */
 enum pldm_state_set_operational_running_status_values {