sepolicy: cnd: Allow access to wifi_prop

[    9.846720] type=1400 audit(61515473.570:12): avc: denied { read } for comm="cnd" name="u:object_r:wifi_prop:s0" dev="tmpfs" ino=13866 scontext=u:r:cnd:s0 tcontext=u:object_r:wifi_prop:s0 tclass=file permissive=1
[    9.847037] type=1400 audit(61515473.570:13): avc: denied { open } for comm="cnd" path="/dev/__properties__/u:object_r:wifi_prop:s0" dev="tmpfs" ino=13866 scontext=u:r:cnd:s0 tcontext=u:object_r:wifi_prop:s0 tclass=file permissive=1
[   11.598514] type=1400 audit(61515473.570:14): avc: denied { getattr } for comm="cnd" path="/dev/__properties__/u:object_r:wifi_prop:s0" dev="tmpfs" ino=13866 scontext=u:r:cnd:s0 tcontext=u:object_r:wifi_prop:s0 tclass=file permissive=1

Change-Id: Ie88ab998f7a139f118c4ceb5192579644222e162
(cherry picked from commit d71bbd47dabc685a18dd32d563a50e95f465554b)