label extcon files

Bug: 199748390
Test: boot with those files labeled
09-13 17:01:44.542  1865  1865 I auditd  : type=1400 audit(0.0:5):
avc: denied { read } for comm="android.ui" name="extcon3" dev="sysfs"
ino=61612 scontext=u:r:system_server:s0 tcontext=u:object_r:sysfs:s0
tclass=dir permissive=0
Change-Id: Iabab1243ce7259d46040901a2a734b5962d281a5
1 file changed