healthd: charger: Add backlight control in charging animation

On some targets the FBIOBLANK does not control the backlight. Add the
backlight control in charging animation to make sure the backlight will
be turned on/off successfully.

Change-Id: I3bba3b58daba6cffa4eb1314a6da1542f43e8e47

healthd: remove useless gotos in set_backlight_on

Change-Id: Id2a254eade02a10da699a8293ae988e9ee53be80

Disable backlight when blanking panel.

This used to be the behaviour up to and including cm-11.0 (see e.g.
commit f7ce72ca), but in newer versions the backlight is only turned on
and never off (see commit 1e961c04). Fix it.

Change-Id: I6c3bf6abbb4e11dc010c360ecfe9f3bb3e2f3548

healthd: Add secondary backlight path support

Some devices require two backlight brightness
paths to turn off the screen.

Change-Id: Ibf2ee853657c602158af219de0ba132f29dc4571

Change-Id: I3bba3b58daba6cffa4eb1314a6da1542f43e8e47