In the case of defer probe we should not print an error message.

This also aligns with how defer probe is handled in the other GPIOs
used by this driver.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Tested-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>