drm/amdgpu: log when amdgpu.dc=1 but ASIC is unsupported

This makes it easier to figure out whether the kernel parameter has been
taken into account.

Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Harry Wentland <hwentlan@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -2636,6 +2636,9 @@ bool amdgpu_device_asic_has_dc_support(enum amd_asic_type asic_type)
 		return amdgpu_dc != 0;
 #endif
 	default:
+		if (amdgpu_dc > 0)
+			DRM_INFO("Display Core has been requested via kernel parameter "
+					 "but isn't supported by ASIC, ignoring\n");
 		return false;
 	}
 }