drivers/task_manager: Add missing return value and missing break
drivers/task_manager: Add missing return value and missing break

1. if no error, ret value should be set to OK.
2. TMIOC_TERMINATE case misses break syntax.

jeongarmy/TizenRT,an4967/TizenRT,chanijjani/TizenRT,JeonginKim/TizenRT,sunghan-chang/TizenRT,davidfather/TizenRT,jeongarmy/TizenRT,jeongarmy/TizenRT,an4967/TizenRT,junmin-kim/TizenRT,Samsung/TizenRT,chanijjani/TizenRT,chanijjani/TizenRT,jeongchanKim/TizenRT,JeonginKim/TizenRT,davidfather/TizenRT,jeongchanKim/TizenRT,jeongchanKim/TizenRT,JeonginKim/TizenRT,sunghan-chang/TizenRT,davidfather/TizenRT,jsdosa/TizenRT,JeonginKim/TizenRT,jsdosa/TizenRT,jeongchanKim/TizenRT,junmin-kim/TizenRT,pillip8282/TizenRT,an4967/TizenRT,jsdosa/TizenRT,HONGCHAEHEE/TizenRT,Samsung/TizenRT,davidfather/TizenRT,junmin-kim/TizenRT,jeongarmy/TizenRT,sunghan-chang/TizenRT,JeonginKim/TizenRT,an4967/TizenRT,jeongarmy/TizenRT,jsdosa/TizenRT,pillip8282/TizenRT,jeongchanKim/TizenRT,Samsung/TizenRT,an4967/TizenRT,davidfather/TizenRT,JeonginKim/TizenRT,davidfather/TizenRT,jsdosa/TizenRT,junmin-kim/TizenRT,HONGCHAEHEE/TizenRT,Samsung/TizenRT,jeongchanKim/TizenRT,an4967/TizenRT,Samsung/TizenRT,junmin-kim/TizenRT,HONGCHAEHEE/TizenRT,junmin-kim/TizenRT,pillip8282/TizenRT,HONGCHAEHEE/TizenRT,chanijjani/TizenRT,HONGCHAEHEE/TizenRT,jeongarmy/TizenRT,jsdosa/TizenRT,pillip8282/TizenRT,sunghan-chang/TizenRT,sunghan-chang/TizenRT,davidfather/TizenRT,jeongarmy/TizenRT,jeongchanKim/TizenRT,jsdosa/TizenRT,junmin-kim/TizenRT,pillip8282/TizenRT,HONGCHAEHEE/TizenRT,pillip8282/TizenRT,Samsung/TizenRT,pillip8282/TizenRT,Samsung/TizenRT,an4967/TizenRT,chanijjani/TizenRT,sunghan-chang/TizenRT,sunghan-chang/TizenRT,chanijjani/TizenRT,chanijjani/TizenRT