Revert "samsung: doze: Add back button to action bar"

Starting N, top-level Settings activities should a drawer menu up
on the action bar. Remove the up/back button as it is now obsolete.

This reverts commit 5cfd7e76cf8099ebd22f4580cac8ed2217c3ead4.

Change-Id: I07af4c08a12bafbef424d01f62521cf226abbc2f
1 file changed