drm/exynos: use drm_calloc_large when allocates pointer array

If the type of object is pointer array, the drm_calloc_large() is
more suitable than kzalloc() for its allocation function. And uses
drm_free_large() instead of kfree() also.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>