FP2-1340: use board date feature in the clock widget

Fix board date permissions so SystemUI can access them.
JIRA ID:FPII-1340

Change-Id: I5beca252b2f61521b765834ad8e54ed49a70a67b
diff --git a/platform_app.te b/platform_app.te
index 7ff8d62..e834032 100644
--- a/platform_app.te
+++ b/platform_app.te
@@ -27,3 +27,7 @@
 # Write to /cache.
 allow platform_app cache_file:dir create_dir_perms;
 allow platform_app cache_file:file create_file_perms;
+
+# /persist -> board date lives there, so access is needed within SystemUI
+allow platform_app persist_file:dir r_dir_perms;
+allow platform_app persist_file:file r_file_perms;