ISharedSecret: Add strongbox definition

Bug: 188728065
Change-Id: I0cbf50f385b00a90c3647e67f34527f21131985a
diff --git a/compatibility_matrices/compatibility_matrix.6.xml b/compatibility_matrices/compatibility_matrix.6.xml
index 01cd1f6..aee2c51 100644
--- a/compatibility_matrices/compatibility_matrix.6.xml
+++ b/compatibility_matrices/compatibility_matrix.6.xml
@@ -508,6 +508,7 @@
         <interface>
             <name>ISharedSecret</name>
             <instance>default</instance>
+            <instance>strongbox</instance>
         </interface>
     </hal>
     <hal format="hidl" optional="true">
diff --git a/compatibility_matrices/compatibility_matrix.current.xml b/compatibility_matrices/compatibility_matrix.current.xml
index 3b84b6e..8b6e841 100644
--- a/compatibility_matrices/compatibility_matrix.current.xml
+++ b/compatibility_matrices/compatibility_matrix.current.xml
@@ -508,6 +508,7 @@
         <interface>
             <name>ISharedSecret</name>
             <instance>default</instance>
+            <instance>strongbox</instance>
         </interface>
     </hal>
     <hal format="hidl" optional="true">