Support reading /sys/board_properties/virtualkeys.xxx for virtual keys on touchscreen

Change-Id: I5ce4e8995accc46971aff93a5261a4d15e1f7b58
diff --git a/sepolicy/genfs_contexts b/sepolicy/genfs_contexts
new file mode 100644
index 0000000..56e8950
--- /dev/null
+++ b/sepolicy/genfs_contexts
@@ -0,0 +1 @@
+genfscon sysfs /board_properties u:object_r:sysfs_board_properties:s0