allow system server to read extcon state and type from sysfs

The target device needs to lable the SoC's extcons to sysfs_extcon in
the device's vendor sepolicy to allow the system_server access.

Bug: 152245127
Bug: 193492798
Bug: 193114615
Test: pressubmit and manual
Change-Id: Ib0a90ac5ce2c9437b19d6dc1e0b2cc50fed41dc3
1 file changed