disp: msm: sde: update uidle wd timer load value

Update the uidle wd timer load value to 12. This change will allow
a 10us wd timer per power team reccomendation.

Change-Id: I8a654fc1f70886c75c077e77c926bebf3bad2305
Signed-off-by: Samantha Tran <samtran@codeaurora.org>