drm/i915/gem: Specify address type for chained reloc batches

It is required that a chained batch be in the same address domain as its
parent, and also that must be specified in the command for earlier gen
as it is not inferred from the chaining until gen6.

Fixes: 964a9b0f611e ("drm/i915/gem: Use chained reloc batches")
Signed-off-by: Chris Wilson <[e-mail]>
Reviewed-by: Tvrtko Ursulin <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

···
 	GEM_BUG_ON(cache->rq_size + RELOC_TAIL > PAGE_SIZE  / sizeof(u32));
 	cmd = cache->rq_cmd + cache->rq_size;
 	*cmd++ = MI_ARB_CHECK;
-	if (cache->gen >= 8) {
+	if (cache->gen >= 8)
 		*cmd++ = MI_BATCH_BUFFER_START_GEN8;
-		*cmd++ = lower_32_bits(batch->node.start);
-		*cmd++ = upper_32_bits(batch->node.start);
-	} else {
+	else if (cache->gen >= 6)
 		*cmd++ = MI_BATCH_BUFFER_START;
-		*cmd++ = lower_32_bits(batch->node.start);
-	}
+	else
+		*cmd++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
+	*cmd++ = lower_32_bits(batch->node.start);
+	*cmd++ = upper_32_bits(batch->node.start); /* Always 0 for gen<8 */
 	i915_gem_object_flush_map(cache->rq_vma->obj);
 	i915_gem_object_unpin_map(cache->rq_vma->obj);
 	cache->rq_vma = NULL;