drm/exynos: remove duplicated error routine and unnecessary assign

There were duplicated error handling routines during allocating
pages in lowlevel_buffer_allocate() and g2d_userptr_get_dma_addr().
Also unnecessary NULL assignments for variable used not any more
are removed from g2d_userptr_get_dma_addr() and
g2d_userptr_put_dma_addr().

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.c b/drivers/gpu/drm/exynos/exynos_drm_buf.c
index 518b6d8..b8ac06d 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_buf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_buf.c
@@ -68,8 +68,8 @@
 					&buf->dma_attrs);
 		if (!buf->kvaddr) {
 			DRM_ERROR("failed to allocate buffer.\n");
-			drm_free_large(buf->pages);
-			return -ENOMEM;
+			ret = -ENOMEM;
+			goto err_free;
 		}
 
 		start_addr = buf->dma_addr;
@@ -106,7 +106,7 @@
 	dma_free_attrs(dev->dev, buf->size, buf->pages,
 			(dma_addr_t)buf->dma_addr, &buf->dma_attrs);
 	buf->dma_addr = (dma_addr_t)NULL;
-
+err_free:
 	if (!is_drm_iommu_supported(dev))
 		drm_free_large(buf->pages);