No more double-swiping to toggle panels on tablets.

This also fixes up the drag regions so that quick settings
is only assigned the right 1/3 of the display (or 100dp,
whichever is larger). It had been that more than half of the
status bar, when dragged, would pull down QS.

Bug: 7217002
Change-Id: I515b6e19deab305b99784c7287d8f04fa9b22dc7