nvidiactl: Load drm_ttm_helper module

Since 577.144, the nvidia driver requires the drm_ttm_helper module, so
load it. Of course, it would be better, if modprobe would resolve this
automatically, but we currently don't know why this is not working.

nvidiactl/nvidiactl

@@ -63,6 +63,7 @@ ln -sf /usr/share/nvidia/${nvver} /node/usr_share_mxgfx
 
 test -e /lib/modules/$kver/kernel/drivers/gpu/drm/drm.ko && modprobe drm
 test -e /lib/modules/$kver/kernel/drivers/gpu/drm/drm_kms_helper.ko && modprobe drm_kms_helper
+test -e /lib/modules/$kver/kernel/drivers/gpu/drm/drm_ttm_helper.ko && modprobe drm_ttm_helper
 
 insmod ${nvlink}/nvidia.ko