drm/amdgpu: cleanup coding style in amdkfd a bit

Make the code a bit more readable by using a common
error handling pattern.
Signed-off-by: Bernard Zhao <bernard@vivo.com>
Reviewed-by: Christian König <christian.koenig@amd.com>.
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -660,15 +660,15 @@ static int reserve_bo_and_vm(struct kgd_mem *mem,
 
 	ret = ttm_eu_reserve_buffers(&ctx->ticket, &ctx->list,
 				     false, &ctx->duplicates);
-	if (!ret)
-		ctx->reserved = true;
-	else {
-		pr_err("Failed to reserve buffers in ttm\n");
+	if (ret) {
+		pr_err("Failed to reserve buffers in ttm.\n");
 		kfree(ctx->vm_pd);
 		ctx->vm_pd = NULL;
+		return ret;
 	}
 
-	return ret;
+	ctx->reserved = true;
+	return 0;
 }
 
 /**
@@ -733,17 +733,15 @@ static int reserve_bo_and_cond_vms(struct kgd_mem *mem,
 
 	ret = ttm_eu_reserve_buffers(&ctx->ticket, &ctx->list,
 				     false, &ctx->duplicates);
-	if (!ret)
-		ctx->reserved = true;
-	else
-		pr_err("Failed to reserve buffers in ttm.\n");
-
 	if (ret) {
+		pr_err("Failed to reserve buffers in ttm.\n");
 		kfree(ctx->vm_pd);
 		ctx->vm_pd = NULL;
+		return ret;
 	}
 
-	return ret;
+	ctx->reserved = true;
+	return 0;
 }
 
 /**