drm/exynos/ipp: simplify memory check function

The only thing function should check is if there are buffers in respective
queues.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

diff --cc drivers/gpu/drm/exynos/exynos_drm_ipp.c
Simple merge