msm: mdss: Use workqueue to send panel commands

Sending panel commands is known to be expensive, honor this by
scheduling this task. Also check for panel state and send commands
only when we're actually awake.

These fixes adress bug reports regarding behaviour during boot.
cpufreq: interactive: add back mistakenly removed code, otherwise bc73b24b2751d9a7d4facfef33ad245e48eef753would be pretty much useless.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>