sepolicy: Add iorap_prefetcherd rules

/system/bin/iorapd fork+execs into /system/bin/iorap_prefetcherd during
startup

See also go/android-iorap-security for the design doc

Bug: 137403231
Change-Id: Ie8949c7927a98e0ab757bc46230c589b5a496360
diff --git a/private/iorap_prefecherd.te b/private/iorap_prefecherd.te
new file mode 100644
index 0000000..9ddb512
--- /dev/null
+++ b/private/iorap_prefecherd.te
@@ -0,0 +1,4 @@
+typeattribute iorap_prefetcherd coredomain;
+
+init_daemon_domain(iorap_prefetcherd)
+tmpfs_domain(iorap_prefetcherd)