hwmon: (pwm-fan) Silence error on probe deferral

[ Upstream commit 9f67f7583e77fe5dc57aab3a6159c2642544eaad ]

Probe deferrals aren't actual errors, so silence the error message in
case the PWM cannot yet be acquired.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>