drm/i915/selftests: Set always_coherent to false when reading from CPU

Commit 8d4ba9f ("drm/i915/selftests: Pick correct caching mode.")
was not complete  as for non LLC  sharing platforms cpu read can happen
from LLC which probably doesn't have the latest changes made by GPU.

Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Jonathan Cavitt <jonathan.cavitt@intel.com>
Fixes: 8d4ba9f ("drm/i915/selftests: Pick correct caching mode.")
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240516151403.2875-1-nirmoy.das@intel.com
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
(cherry picked from commit 007ed70)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Author: nirmoy

drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c

@@ -196,7 +196,7 @@ static int verify_access(struct drm_i915_private *i915,
 	if (err)
 		goto out_file;
 
-	mode = intel_gt_coherent_map_type(to_gt(i915), native_obj, true);
+	mode = intel_gt_coherent_map_type(to_gt(i915), native_obj, false);
 	vaddr = i915_gem_object_pin_map_unlocked(native_obj, mode);
 	if (IS_ERR(vaddr)) {
 		err = PTR_ERR(vaddr);