leds: aw200xx: Fix error code in probe()

The "ret" variable is zero/success here.  Don't return that, return
-EINVAL instead.

Fixes: 36a87f37 ("leds: Add AW20xx driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/4d791b69-01c7-4532-818c-63712d3f63e1@moroto.mountain


Signed-off-by: Lee Jones <lee@kernel.org>