sepolicy: add /vendor to file_contexts

/vendor has the same permissions as /system/vendor for devices
that have a separate vendor partition.

Bug: 8341435
Change-Id: If0c78b31f8a6e8e5680f1d076c323d1628fb07b2

file_contexts

@@ -140,6 +140,11 @@
 /system/xbin/su		u:object_r:su_exec:s0
 /system/vendor/bin/gpsd u:object_r:gpsd_exec:s0
 #############################
+# Vendor files
+#
+/vendor(/.*)?		u:object_r:system_file:s0
+/vendor/bin/gpsd	u:object_r:gpsd_exec:s0
+#############################
 # Data files
 #
 /data(/.*)?		u:object_r:system_data_file:s0