anv: Add an instance multiplier to anv_pipeline

This lets us get rid of the view_mask and pipeline replication logic
repeated all over everywhere.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17564>

src/intel/vulkan/anv_private.h

@@ -3352,6 +3352,7 @@ struct anv_graphics_pipeline {
    VkColorComponentFlags                        color_comp_writes[MAX_RTS];
 
    uint32_t                                     view_mask;
+   uint32_t                                     instance_multiplier;
 
    bool                                         writes_depth;
    bool                                         depth_test_enable;