Add back in SuperSU to VentureROM

Previously added here https://github.com/DirtyUnicorns/android_build/commit/89c148187a96f81c4db1d17e5e34f6c7f6eeb9c3

Credit/Thanks to LorDClockaN and AICP

Change-Id: I2e52ed4728523aaaa48e5d605b920871ad9aa1cd