sepolicy: Allow cmupdater/uncrypt access to media_rw_data_file

Change-Id: I800584af2919e3397b19d229fc28ad50cc4b2730
diff --git a/sepolicy/uncrypt.te b/sepolicy/uncrypt.te
new file mode 100644
index 0000000..8fddf8a
--- /dev/null
+++ b/sepolicy/uncrypt.te
@@ -0,0 +1 @@
+r_dir_file(uncrypt, media_rw_data_file)