priv_app: remove more logspam

avc: denied { read } for name="ext4" dev="sysfs" ino=32709
scontext=u:r:priv_app:s0:c512,c768 tcontext=u:object_r:sysfs:s0
tclass=dir permissive=0 b/72749888
avc: denied { read } for name="state" dev="sysfs" ino=51318
scontext=u:r:priv_app:s0:c512,c768
tcontext=u:object_r:sysfs_android_usb:s0 tclass=file permissive=0
b/72749888

Bug: 72749888
Test: build/boot taimen-userdebug. No more logspam
Change-Id: Ic43d1c8b71e1e5e0e6f9af1e03816c4084120e7e