drm/amdgpu: make function pointers mandatory

We always want those to be setup correctly.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/tonga_ih.c b/drivers/gpu/drm/amd/amdgpu/tonga_ih.c
index 52853d8..a79a377 100644
--- a/drivers/gpu/drm/amd/amdgpu/tonga_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/tonga_ih.c
@@ -513,8 +513,7 @@ static const struct amdgpu_ih_funcs tonga_ih_funcs = {
 
 static void tonga_ih_set_interrupt_funcs(struct amdgpu_device *adev)
 {
-	if (adev->irq.ih_funcs == NULL)
-		adev->irq.ih_funcs = &tonga_ih_funcs;
+	adev->irq.ih_funcs = &tonga_ih_funcs;
 }
 
 const struct amdgpu_ip_block_version tonga_ih_ip_block =