Modify GPS Tile

Credits to kufikugel, https://github.com/SlimRoms/frameworks_base/commit/8771828d85593907063d15c5181c5a2c49bf445b

Only able to switch between Location off <-> Device only, Battery saving <-> Location off

remove unused string
click to turn it on/off, long click to switch between three states

Change-Id: I2f1d122a8901229e37b4ea1461f52f7c4cdc9633