mediaserver: remove access to 'sysfs' type.

Bug: 65643247
Test: cts-tradefed run cts-dev -m \
CtsMediaTestCases --compatibility:module-arg \
CtsMediaTestCases:include-annotation:\
android.platform.test.annotations.RequiresDevice
No denials from mediaserver domain to sysfs type are observed.
Change-Id: Icb5c12f04af213452d82e226993fe13085c5c33f