disp: msm: sde: update dim layer check during secure transition

This change updates check for dim layer while transitioning
to secure UI if no planes are staged in previous commit.

Change-Id: Iba4a3cf58043a974647c0aabd38cad6d5522169b
Signed-off-by: Yashwanth <yvulapu@codeaurora.org>