mango: Remove obsolete ALS configuration

Also set button_backlight current on pre_hw_config.sh to avoid too bright recovery indication.

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

Change-Id: I948e9495917b94e4995c5cdffff933004d802a5c
Merge "mango: Remove obsolete ALS configuration" into jellybean