Allow init to set context for super_block_device

Fixes the following denial during boot:

[    1.358156] selinux: SELinux: Could not set context for
/dev/block/platform/soc/1d84000.ufshc/by-name/super:  Permission denied\x0a
[    1.358275] audit: type=1400 audit(951562.676:7):
avc:  denied  { relabelto } for  pid=1 comm="init" name="super"
dev="tmpfs" ino=17657 scontext=u:r:init:s0 tcontext=u:object_r:super_block_device:s0
tclass=lnk_file permissive=0

Bug: 124410201
Test: make
Change-Id: Ib6752b8a6ae4211ba8c0a7417295b8144a2fed67
diff --git a/public/init.te b/public/init.te
index c5b88d2..87e8901 100644
--- a/public/init.te
+++ b/public/init.te
@@ -46,6 +46,8 @@
   userdata_block_device
 }:{ blk_file lnk_file } relabelto;
 
+allow init super_block_device:lnk_file relabelto;
+
 # Create /mnt/sdcard -> /storage/self/primary symlink.
 allow init mnt_sdcard_file:lnk_file create;