Deprecate HIDL android.system.wifi.keystore interface

This functionality is replaced by new methods added to
android.hardware.wifi.supplicant.

Test: None
Bug: 205764502
Change-Id: Ib1dc238c7a0609bccafec0b9fd7e90b48396d6ac
diff --git a/vintfdata/manifest.xml b/vintfdata/manifest.xml
index b3d84aa..b93205c 100644
--- a/vintfdata/manifest.xml
+++ b/vintfdata/manifest.xml
@@ -54,7 +54,7 @@
             <instance>default</instance>
         </interface>
     </hal>
-    <hal format="hidl">
+    <hal format="hidl" max-level="7">
         <name>android.system.wifi.keystore</name>
         <transport>hwbinder</transport>
         <version>1.0</version>