Button & keyboard backlight brightness adjustment (1/2)

PS2: move from display to button settings
PS3: fix tab

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I35a6d149affc1da08707b7c40fb02761321cba41
Merge remote-tracking branch 'cm/cm-10.2' into cm-10.2