Avoid a compiler warnings when the val parameter is an expression.
This is based on commit 5843f4e02fbe86a59981e35adc6cabebee46fdc0 from
Linux v4.16-rc1.
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Tested-by: Andre Heider <a.heider@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>