hwc: vds: Add support for black frame generation on PWR suspend

If VDS is connected, do not clear WB object as it will end up
detaching IOMMU. We need to keep the WB session active in order
to send a black frame to WFD sink on power suspend.

For AD use case, we will keep the WB object active.

Change-Id: Ic6db255676ca0baafd468887fc3f88eafc581cea
1 file changed