drm/amd: Limit seamless boot by default to APUs

A hang is reported on DCN 3.2 with seamless boot enabled.
As the benefits come from an eDP setup, limit it to only enabled
by default with APUs.

Suggested-by: Alexander.Deucher@amd.com
Reported-by: feifei.xu@amd.com
Closes: https://lore.kernel.org/amd-gfx/85b427f6-11ec-4249-bf6f-eadf9c375f88@amd.com/T/#m2887e919d7c01b2a4860d2261b366d22e070f309Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1380,6 +1380,9 @@ bool amdgpu_device_seamless_boot_supported(struct amdgpu_device *adev)
 		return false;
 	}
 
+	if (!(adev->flags & AMD_IS_APU))
+		return false;
+
 	if (adev->mman.keep_stolen_vga_memory)
 		return false;