drm/exynos: Use pm_runtime_resume_and_get() to replace open coding

use pm_runtime_resume_and_get() to replace pm_runtime_get_sync and
pm_runtime_put_noidle to avoid continuing to increase the refcount
when pm_runtime_get_sync fails.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Inki Dae <inki.dae@samsung.com>