panvk: omit ZS in color preload target mask
The color preload shader does not write to depth/stencil, and
render_target_mask
does not support tracking depth/stencil dependencies
anyway.
This was causing assertion failures when using depth/stencil attachments
with VK_ATTACHMENT_LOAD_OP_LOAD
, because depth/stencil attachments are
tracked in bits 8 and 9, which do not fit into the 8-bit mask.
I first ran into this while working on multiview, with the dEQP-VK.multiview.depth.*
tests, but presumably there are other CTS tests that will trigger it.