led: leds-qpnp: Add work queue to LED driver

Regulator operation requires non-atomic context and current driver
does not put LED to sleep. This causes APPs crash. By introducing
work queue, the problem is solved.

Signed-off-by: Chun Zhang <chunz@codeaurora.org>
(cherry picked from commit 815a1832a1027015bfaec902ef1d76eb8c4cfc5e)

Change-Id: Ia011073d44f07603a913f110ffd92868e3102deb
Signed-off-by: Sunil Joseph <jsunil@codeaurora.org>
Merge "led: leds-qpnp: Add work queue to LED driver"