msm: mdss: add support to call panel events for one panel

Add support in the panel interface to apply the requested
events to the panel pointed by the controller only,
this will give the caller the choice to skip the loop
in all the child panels of the interface.

Change-Id: I86edfadb6e326354914b79c284feb10837e83245
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>