msm: mdss: mdp: fix to prevent early wake up if panel is off

Current code request the power transition during the
early wake up event even if the panel is off.
This is can cause problems due ctl is not valid at this
time or in some other race conditions it prevents the
bandwidth requests. This fix prevents that early wake up
is called during power off, fixing the null pointer
dereferences and mdp busy timouts errors.

Change-Id: Idc51d02aa34d794a38f6e3a82ae80d5afa3d58f4
Signed-off-by: Vinu Deokaran <vinud@codeaurora.org>
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>