drm/i915/guc: Return NULL for missing multi-lrc parent

multi_lrc_create_parent() returns ERR_PTR(0) when there are not enough
engines in the class to create a parallel context.  ERR_PTR(0) evaluates
to NULL, and the only caller already treats NULL as the non-error
"not enough engines" case.

Return NULL directly to make the non-error path explicit.

Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
Link: https://lore.kernel.org/r/20260706071412.559909-1-lilinmao@kylinos.cn
This commit is contained in:
Linmao Li 2026-07-06 15:14:08 +08:00 • committed by Tvrtko Ursulin
commit ca1dc06173