Revert^2 "Add qemu.hw.mainkeys to system property_contexts"

509b35e5d9b72f725d17fab35ecb11b9b706a399

Bug: 180412668
Merged-In: I4067bba36613fa41e3c7a085da76cda4784753ad
Change-Id: I4067bba36613fa41e3c7a085da76cda4784753ad
diff --git a/private/system_server.te b/private/system_server.te
index c143999..4796b89 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -1328,3 +1328,6 @@
 # Only system server can write the font files.
 neverallow { domain -init -system_server } font_data_file:file no_w_file_perms;
 neverallow { domain -init -system_server } font_data_file:dir no_w_dir_perms;
+
+# Read qemu.hw.mainkeys property
+get_prop(system_server, qemu_hw_prop)