system.prop: update for d855

Change-Id: Ifb10a64541b530f5940681e71a6f6cc4067d40a9
d855: set correct system partition size

Change-Id: I8fad9a140dac8e81de248bb7302a884c24c6f468
d855: update fstab

* add recoveryonly to boot and recovery partitions
* update deprecated prefix on usb/externalsd
* set auto for usb/externalsd filesystem

Change-Id: I9dfca66f45b6c51f0c6c8d11ca812490457e42ec