Move mounting from devices to common place

Bug: 130377452
Test: boot to home with firmware and persist image mounted
Change-Id: I30e7dad45a94522a45e64dfb86363723d96bd4dc
diff --git a/common/file.te b/common/file.te
new file mode 100644
index 0000000..7dc080d
--- /dev/null
+++ b/common/file.te
@@ -0,0 +1,4 @@
+type persist_file, file_type, vendor_persist_type;
+type firmware_file, file_type, contextmount_type, vendor_file_type;
+
+allow firmware_file self:filesystem associate;