storage: add fastbootd sepolicy

We need to format the /metadata partition in fastbootd mode.
This CL aims to include the necessary SELinux rules.

Bug: 264489957
Test: rom flashing
Change-Id: Ib94dbcb580c0a16395b48b8eeef6e431a637d235
Signed-off-by: Randall Huang <huangrandall@google.com>
diff --git a/storage/sepolicy/fastbootd.te b/storage/sepolicy/fastbootd.te
new file mode 100644
index 0000000..35bac15
--- /dev/null
+++ b/storage/sepolicy/fastbootd.te
@@ -0,0 +1 @@
+allow fastbootd devpts:chr_file rw_file_perms;