allow init to read symlinks in sys

avc: denied { read } for name="device" dev="sysfs" ino=36099 scontext=u:r:init:s0 tcontext=u:object_r:sysfs_rmtfs:s0 tclass=lnk_file

init is already allowed to read directories, this is an obvious omission.

Change-Id: I5131a84bb67e73aaed235c3cbab95c365eaaa2f0