Fix the secure flag check for blackout layer issue

When there is a layer not to be composed on insecure virtual display,
surfaceflinger will send a black color layer to render engine to
compose instead of the original buffer.

If render engine supports protected context, but layer does not set
the eLayerSecure flag,the layer will not be set to black color layer
and will be sent to render engine to compose on the insecure display
based on current logic, even if the layer buffer usage is protected.

Solution: add buffer usage check for insecure display case.
Test result: The secure layer buffer will not be sent to render engine
for the insecure virtual display to compose, and a black color layer
will be sent instead.

Bug: 185195873
Test: By partner
Change-Id: Iad53411ea642fee3e5b09222760a223b4ada61ad