anv: fix push constant subgroup_id location

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 7c76125db2 ("anv: use 2 different buffers for surfaces/samplers in descriptor sets")
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25814>

src/intel/vulkan/anv_private.h

@@ -3423,6 +3423,12 @@ struct anv_push_constants {
     */
    uint32_t surfaces_base_offset;
 
+   /* Robust access pushed registers. */
+   uint64_t push_reg_mask[MESA_SHADER_STAGES];
+
+   /** Ray query globals (RT_DISPATCH_GLOBALS) */
+   uint64_t ray_query_globals;
+
    union {
       struct {
          /** Dynamic MSAA value */
@@ -3443,16 +3449,12 @@ struct anv_push_constants {
           *
           * This is never set by software but is implicitly filled out when
           * uploading the push constants for compute shaders.
+          *
+          * This *MUST* be the last field of the anv_push_constants structure.
           */
          uint32_t subgroup_id;
       } cs;
    };
-
-   /* Robust access pushed registers. */
-   uint64_t push_reg_mask[MESA_SHADER_STAGES];
-
-   /** Ray query globals (RT_DISPATCH_GLOBALS) */
-   uint64_t ray_query_globals;
 };
 
 struct anv_surface_state {