Add microdroid specific sepolicy

Microdroid will have a separate sepolicy, apart from the core policy.
This is the first step; For now it's a simple copy of system/sepolicy.
For the future work, it will be stripped.

Bug: 189165759
Test: boot microdroid and see selinux enforced
Change-Id: I2fee39f7231560b49c93bd5e8d0feeffada40938
diff --git a/microdroid/sepolicy/system/private/fsck.te b/microdroid/sepolicy/system/private/fsck.te
new file mode 100644
index 0000000..4d68fa5
--- /dev/null
+++ b/microdroid/sepolicy/system/private/fsck.te
@@ -0,0 +1,7 @@
+typeattribute fsck coredomain;
+
+init_daemon_domain(fsck)
+
+allow fsck metadata_block_device:blk_file rw_file_perms;
+
+allow fsck vd_device:blk_file rw_file_perms;