drm/i915: Fix one wrong caching mode enum usage

Commit a4d86249 ("drm/i915/gt: Provide a utility to create a scratch
buffer") mistakenly passed in uapi I915_CACHING_CACHED as argument to
i915_gem_object_set_cache_coherency(), which actually takes internal
enum i915_cache_level.

No functional issue since the value matches I915_CACHE_LLC (1 == 1), which
is the intended caching mode, but lets clean it up nevertheless.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: a4d86249 ("drm/i915/gt: Provide a utility to create a scratch buffer")
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230707125503.3965817-1-tvrtko.ursulin@linux.intel.com
(cherry picked from commit 49c60b2f)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drivers/gpu/drm/i915/gt/intel_gtt.c

@@ -670,7 +670,7 @@ __vm_create_scratch_for_read(struct i915_address_space *vm, unsigned long size)
 	if (IS_ERR(obj))
 		return ERR_CAST(obj);
 
-	i915_gem_object_set_cache_coherency(obj, I915_CACHING_CACHED);
+	i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC);
 
 	vma = i915_vma_instance(obj, vm, NULL);
 	if (IS_ERR(vma)) {