drm/amd/amdgpu: hide #warning for missing DC config

It is annoying to have #warnings that trigger in randconfig
builds like

drivers/gpu/drm/amd/amdgpu/soc15.c:653:3: error: "Enable CONFIG_DRM_AMD_DC for display support on SOC15."
drivers/gpu/drm/amd/amdgpu/nv.c:400:3: error: "Enable CONFIG_DRM_AMD_DC for display support on navi."

Remove these and rely on the users to turn these on.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -392,8 +392,6 @@ int nv_set_ip_blocks(struct amdgpu_device *adev)
 #if defined(CONFIG_DRM_AMD_DC)
 		else if (amdgpu_device_has_dc_support(adev))
 			amdgpu_device_ip_block_add(adev, &dm_ip_block);
-#else
-#	warning "Enable CONFIG_DRM_AMD_DC for display support on navi."
 #endif
 		amdgpu_device_ip_block_add(adev, &gfx_v10_0_ip_block);
 		amdgpu_device_ip_block_add(adev, &sdma_v5_0_ip_block);

drivers/gpu/drm/amd/amdgpu/soc15.c

@@ -649,8 +649,6 @@ int soc15_set_ip_blocks(struct amdgpu_device *adev)
 #if defined(CONFIG_DRM_AMD_DC)
 		else if (amdgpu_device_has_dc_support(adev))
 			amdgpu_device_ip_block_add(adev, &dm_ip_block);
-#else
-#	warning "Enable CONFIG_DRM_AMD_DC for display support on SOC15."
 #endif
 		if (!(adev->asic_type == CHIP_VEGA20 && amdgpu_sriov_vf(adev))) {
 			amdgpu_device_ip_block_add(adev, &uvd_v7_0_ip_block);
@@ -671,8 +669,6 @@ int soc15_set_ip_blocks(struct amdgpu_device *adev)
 #if defined(CONFIG_DRM_AMD_DC)
 		else if (amdgpu_device_has_dc_support(adev))
 			amdgpu_device_ip_block_add(adev, &dm_ip_block);
-#else
-#	warning "Enable CONFIG_DRM_AMD_DC for display support on SOC15."
 #endif
 		amdgpu_device_ip_block_add(adev, &vcn_v1_0_ip_block);
 		break;