crocus: find correct relocation target for the bo.

If we have batch a + b, and writing to batch b, causes batch a
to flush, all the bo->index get reset, and we try to submit a -1
to the kernel.

Look the bo index up when creating relocations.

Fixes crash seen in KHR-GL46.compute_shader.pipeline-post-fs
and a trace from Wasteland 3

Fixes: f3630548f1 ("crocus: initial gallium driver for Intel gfx 4-7")

Reviewed-by: Zoltán Böszörményi <zboszor@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14905>
(cherry picked from commit 37c3be6947)

Conflicts:
	src/gallium/drivers/crocus/ci/crocus-hsw-flakes.txt

I've deleted this file, which the original removed an entry from as it
doesn't exist, and the CI isn't run on the 22.0 branch.

.pick_status.json

@@ -211,7 +211,7 @@
         "description": "crocus: find correct relocation target for the bo.",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "f3630548f1da904ec6c63b43ece7e68afdb8867e"
     },

src/gallium/drivers/crocus/crocus_batch.c

@@ -263,21 +263,30 @@ crocus_init_batch(struct crocus_context *ice,
    crocus_batch_reset(batch);
 }
 
-static struct drm_i915_gem_exec_object2 *
-find_validation_entry(struct crocus_batch *batch, struct crocus_bo *bo)
+static int
+find_exec_index(struct crocus_batch *batch, struct crocus_bo *bo)
 {
    unsigned index = READ_ONCE(bo->index);
 
    if (index < batch->exec_count && batch->exec_bos[index] == bo)
-      return &batch->validation_list[index];
+      return index;
 
    /* May have been shared between multiple active batches */
    for (index = 0; index < batch->exec_count; index++) {
       if (batch->exec_bos[index] == bo)
-         return &batch->validation_list[index];
+	 return index;
    }
+   return -1;
+}
 
-   return NULL;
+static struct drm_i915_gem_exec_object2 *
+find_validation_entry(struct crocus_batch *batch, struct crocus_bo *bo)
+{
+   int index = find_exec_index(batch, bo);
+
+   if (index == -1)
+      return NULL;
+   return &batch->validation_list[index];
 }
 
 static void
@@ -409,7 +418,7 @@ emit_reloc(struct crocus_batch *batch,
       (struct drm_i915_gem_relocation_entry) {
          .offset = offset,
          .delta = target_offset,
-         .target_handle = target->index,
+         .target_handle = find_exec_index(batch, target),
          .presumed_offset = entry->offset,
       };