Remove KM strongbox instance temporarily

Strongbox is not supported on all devices
and breaks device builds (cf_x86_phone-userdebug).

This change to be relanded once dependencies are resolved.

Test: builds
Bug: 68112778
Change-Id: I846cdbcfdf7d0a76e0c86518da8a1bb4eeed3caa
diff --git a/compatibility_matrices/compatibility_matrix.current.xml b/compatibility_matrices/compatibility_matrix.current.xml
index b500ed4..497071d 100644
--- a/compatibility_matrices/compatibility_matrix.current.xml
+++ b/compatibility_matrices/compatibility_matrix.current.xml
@@ -182,7 +182,6 @@
         <interface>
             <name>IKeymasterDevice</name>
             <instance>default</instance>
-            <instance>strongbox</instance>
         </interface>
     </hal>
     <hal format="hidl" optional="true">