drm/amd/display: Fix the Wunused-function warning

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:941:13: warning: ‘dm_dmub_trace_high_irq’ defined but not used [-Wunused-function]
  941 | static void dm_dmub_trace_high_irq(void *interrupt_params)
      |             ^~~~~~~~~~~~~~~~~~~~~~

Fixes: a08f16cf ("drm/amd/display: Log DMCUB trace buffer events")
Cc: Leo (Hanghong) Ma <hanghong.ma@amd.com>
Cc: Daniel Wheeler <daniel.wheeler@amd.com>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Cc: Solomon Chiu <solomon.chiu@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NShaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -937,6 +937,7 @@ static int dm_dmub_hw_init(struct amdgpu_device *adev)
 	return 0;
 }
 
+#if defined(CONFIG_DRM_AMD_DC_DCN)
 #define DMUB_TRACE_MAX_READ 64
 static void dm_dmub_trace_high_irq(void *interrupt_params)
 {
@@ -963,7 +964,6 @@ static void dm_dmub_trace_high_irq(void *interrupt_params)
 	ASSERT(count <= DMUB_TRACE_MAX_READ);
 }
 
-#if defined(CONFIG_DRM_AMD_DC_DCN)
 static void mmhub_read_system_context(struct amdgpu_device *adev, struct dc_phy_addr_space_config *pa_config)
 {
 	uint64_t pt_base;