extcon: max14577: Fix probe failure on successful work queue

In probe the driver queued delayed work for cable detection and
returned the result of queue_delayed_work() call. However the return
value of queue_delayed_work() does not indicate an error and in normal
condition it returns true which means successful work queue.
This effectively resulted in probe failure:
[    2.088204] max14577-muic: probe of max77836-muic failed with error 1

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: <stable@vger.kernel.org>
Fixes: 962e56bf ("extcon: max14577: Add extcon-max14577 driver...")
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>