Use resource managed interrupt line devm_request_threaded_irq() to
simplify a little cleanup paths:
 - no goto to cleanup label,
 - simpler remove function.

Overall the driver size is decreased by 11 line of code.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>