sdm: Do not copy surfaceDamage rects for SKIP layers

SurfaceFlinger marks HWC_SKIP_LAYER to indicate HWC to skip a layer.
HWC wrapper should not read and copy surfaceDamage rects, as it can
be a random/undefined pointer, which can lead to stack corruption.

CRs-Fixed: 938164
Change-Id: Ie891cc1e5c9b5264a2198cc4f8f07683d78d7bb1
1 file changed