msm: mdss: fix the input layer and layer list array index

In the current implementation, wrong memory is being referenced while
copying to user. Correct the input layer and layer list array index
to avoid invalid memory access.

CRs-Fixed: 882379
Change-Id: I47790d1c5419c099ce32727c28e5e6e7e742f18f
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>