memory: samsung: exynos5422-dmc: Use delayed timer as default

Use delayed timer as default instead of deferrable timer
in order to monitor the DMC status regardless of CPU idle.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>