state-set: Add the enum for Device Power State

As per the spec DSP0249 the PLDM state set Device
Power State [Set ID: 257] can have four enumeration
values defined. This commit adds the unknown, on
and off state in enum for the same.

Change-Id: I8565df98006c183df50d8220db02fdb61a3eae04
Signed-off-by: Riya Dixit <riyadixitagra@gmail.com>
diff --git a/include/libpldm/state_set.h b/include/libpldm/state_set.h
index c3097cb..bddfeb3 100644
--- a/include/libpldm/state_set.h
+++ b/include/libpldm/state_set.h
@@ -234,6 +234,16 @@
 	PLDM_STATE_SET_SYS_POWER_STATE_OFF_SOFT_GRACEFUL = 9
 };
 
+/* @brief List of states for Device Power State set (ID 257).
+ */
+enum pldm_state_set_device_power_state_values {
+	PLDM_STATE_SET_ACPI_DEVICE_POWER_STATE_UNKNOWN = 0,
+	PLDM_STATE_SET_ACPI_DEVICE_POWER_STATE_FULLY_ON = 1,
+	PLDM_STATE_SET_ACPI_DEVICE_POWER_STATE_INTERMEDIATE_1 = 2,
+	PLDM_STATE_SET_ACPI_DEVICE_POWER_STATE_INTERMEDIATE_2 = 3,
+	PLDM_STATE_SET_ACPI_DEVICE_POWER_STATE_OFF = 4,
+};
+
 /* OEM ranges */
 #define PLDM_OEM_STATE_SET_ID_START 32768
 #define PLDM_OEM_STATE_SET_ID_END   65535