Added read only suspend hal properties

Bug: 170587692
Test: Inspected logs to confirm android.system.suspend can access the
properties

Change-Id: Ie6a84afe490df0d2b11ff4f06588c7bca68d9850
diff --git a/private/system_suspend.te b/private/system_suspend.te
index 217548f..857fea8 100644
--- a/private/system_suspend.te
+++ b/private/system_suspend.te
@@ -18,6 +18,9 @@
 # To resolve arbitrary sysfs paths from /sys/class/wakeup/* symlinks.
 allow system_suspend sysfs_type:dir search;
 
+# Access to suspend_hal system properties
+get_prop(system_suspend, suspend_prop)
+
 # To call BTAA registered callbacks
 allow system_suspend bluetooth:binder call;