drm/exynos: use directly DMA mapping APIs on g2d

There is no reason to be wapper functions to use DMA mapping APIs. Use
directly DMA mapping APIs and remove the wapper functions.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
3 files changed