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

[ Upstream commit 9f67f758 ]

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>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I2545bda78f045f04a39f4b9aa98783f4fb70214b