drm/amdgpu: use correct rounding macro for 64-bit

This fixes 32-bit arm build due to lack of 64-bit divides.

Fixes: cb1c814 ("drm/ttm: flip the switch for driver allocated resources v2")
Link: https://patchwork.freedesktop.org/patch/438442/
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c

@@ -407,7 +407,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 #endif
 		pages_per_node = max_t(uint32_t, pages_per_node,
 				       tbo->page_alignment);
-		num_nodes = DIV_ROUND_UP(PFN_UP(mem_bytes), pages_per_node);
+		num_nodes = DIV_ROUND_UP_ULL(PFN_UP(mem_bytes), pages_per_node);
 	}
 
 	node = kvmalloc(struct_size(node, mm_nodes, num_nodes),