drm/i915/gt: Replace 'return' with a fall-through

drm/i915/gt: Replace 'return' with a fall-through

Checkpatch worries that the 'return' before an else clause might be
redundant. In this case, it is avoiding hitting the MISSING_CASE()
warning. Let us appease checkpatch by falling through to the end of the
function, which typically means that we then clean up the unused
wa_list.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122192913.4518-10-chris@chris-wilson.co.uk
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>