drm/amdgpu: Failed to check various return code

Clean up code to quiet the compiler on us failing to check the return
code.

Signed-off-by: Andrew Martin <[e-mail]>
Reviewed-by: Harish Kasiviswanathan <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 {
 	struct amdgpu_bo **bo = (struct amdgpu_bo **) mem_obj;
 
-	amdgpu_bo_reserve(*bo, true);
+	(void)amdgpu_bo_reserve(*bo, true);
 	amdgpu_bo_kunmap(*bo);
 	amdgpu_bo_unpin(*bo);
 	amdgpu_bo_unreserve(*bo);

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

···
 		return;
 
 	amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_CPU);
-	ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
+	(void)ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
 
 	dma_unmap_sgtable(adev->dev, ttm->sg, direction, 0);
 	sg_free_table(ttm->sg);
···
 	}
 
 	amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_CPU);
-	ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
+	(void)ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
 
 	dir = mem->alloc_flags & KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE ?
 				DMA_BIDIRECTIONAL : DMA_TO_DEVICE;
···
 		if (!attachment[i])
 			continue;
 		if (attachment[i]->bo_va) {
-			amdgpu_bo_reserve(bo[i], true);
+			(void)amdgpu_bo_reserve(bo[i], true);
 			if (--attachment[i]->bo_va->ref_count == 0)
 				amdgpu_vm_bo_del(adev, attachment[i]->bo_va);
 			amdgpu_bo_unreserve(bo[i]);
···
 		return -EBUSY;
 	}
 
-	amdgpu_vm_bo_unmap(adev, bo_va, entry->va);
+	(void)amdgpu_vm_bo_unmap(adev, bo_va, entry->va);
 
-	amdgpu_vm_clear_freed(adev, vm, &bo_va->last_pt_update);
+	(void)amdgpu_vm_clear_freed(adev, vm, &bo_va->last_pt_update);
 
-	amdgpu_sync_fence(sync, bo_va->last_pt_update);
+	(void)amdgpu_sync_fence(sync, bo_va->last_pt_update);
 
 	return 0;
 }
···
 {
 	struct amdgpu_bo *bo = mem->bo;
 
-	amdgpu_bo_reserve(bo, true);
+	(void)amdgpu_bo_reserve(bo, true);
 	amdgpu_bo_kunmap(bo);
 	amdgpu_bo_unpin(bo);
 	amdgpu_bo_unreserve(bo);