radv: handle sample locations during explicit depth/stencil transitions

radv: handle sample locations during explicit depth/stencil transitions

From the Vulkan spec 1.1.109,

   "Some implementations may need to evaluate depth image values
    while performing image layout transitions. To accommodate this,
    instances of the VkSampleLocationsInfoEXT structure can be
    specified for each situation where an explicit or automatic
    layout transition has to take place. VkSampleLocationsInfoEXT
    can be chained from VkImageMemoryBarrier structures to provide
    sample locations for layout transitions performed by
    vkCmdWaitEvents and vkCmdPipelineBarrier calls."

This handles explicit depth/stencil layout transitions performed
with CmdWaitEvents() or CmdPipelineBarrier().

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-By: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>