regulator: max14577: Fix invalid return value on DT parse success

This fixes bug introduced in 667a6b7a (regulator: max14577: Add missing
of_node_put). The DTS parsing function returned number of matched
regulators as success status which then was compared against 0 in probe.

Result was a probe fail after successful parsing the DTS:
max14577-regulator: probe of max14577-regulator failed with error 2

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviwed-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>