leds: At disable, set the trigger to default instead of wiping it

Change-Id: I4606b463a94281adefbd6317577252e3f759237e
hammerhead kernel: implement always on rgb led support

When offms is set to 0, configure a single point
duty cycle at the desired led brightness.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Change-Id: I5612720a411b995b3e1720d3fc4e08bed82c8bf7
Merge changes I5612720a,I4606b463 into du44

* changes:
  hammerhead kernel: implement always on rgb led support
  leds: At disable, set the trigger to default instead of wiping it