PEL.Entry: Add Subsystem property

Adding subsystem property to support PEL creation. This subsystem
property can be used to identify a failing area in the system. These
subsystem values can be enums but keeping them as strings can save
decoding effort at the far end. The PEL spec has more than 70 unique
values and these can be extended as new hardware shows up.

Signed-off-by: Vijay Lobo <vijaylobo@gmail.com>
Change-Id: I5de076c167f81780c0121c6482d6a6f5b3c63641
diff --git a/yaml/org/open_power/Logging/PEL/Entry.interface.yaml b/yaml/org/open_power/Logging/PEL/Entry.interface.yaml
index 06f4dee..0ea6ba9 100644
--- a/yaml/org/open_power/Logging/PEL/Entry.interface.yaml
+++ b/yaml/org/open_power/Logging/PEL/Entry.interface.yaml
@@ -1,15 +1,21 @@
-description: >

-    Implement to provide PEL event/error entry attributes.

-properties:

-    - name: Hidden

-      type: boolean

-      default: false

-      description: >

-          Hidden Error - This flag allows events to be placed in a system, but

-          remain hidden from the customer. This event log is visible to

-          development personnel only, e.g. hardware recovered error, etc. No

-          service action is required for this type of errors. In general, when

-          this value is used, the Error Action Flags has the value of

-          "Hidden Error". An event log with this value is used primarily for

-          error thresholding design/code debug or as a record to indicate an

-          error frequency or trend.

+description: >
+    Implement to provide PEL event/error entry attributes.
+properties:
+    - name: Hidden
+      type: boolean
+      default: false
+      description: >
+        Hidden Error - This flag allows events to be placed in a system, but
+        remain hidden from the customer. This event log is visible to
+        development personnel only, e.g. hardware recovered error, etc. No
+        service action is required for this type of errors. In general, when
+        this value is used, the Error Action Flags has the value of
+        "Hidden Error". An event log with this value is used primarily for
+        error thresholding design/code debug or as a record to indicate an
+        error frequency or trend.
+    - name: Subsystem
+      type: string
+      description: >
+        A free form, implementation defined string which uniquely and
+        permanently identifies a specific subsystem string. This field should
+        not be used for programmatic interrogation of an object.