udevd errors (invalid value / invalid substitution type) after !7 merged

Description:

Seeing the following errors upon upgrade to nvidia-dkms 550.76-2 with a1585470:

Apr 23 08:30:03 systemd-udevd[485]: /usr/lib/udev/rules.d/60-nvidia.rules:2 Invalid value "/usr/bin/bash -c '/usr/bin/mknod -Z -m 666 /dev/nvidiactl c $$(grep nvidia$ /proc/devices | cut -d \  -f 1) 255'" for RUN (char 75: invalid substitution type), ignoring.
Apr 23 08:30:03 systemd-udevd[485]: /usr/lib/udev/rules.d/60-nvidia.rules:3 Invalid value "/usr/bin/bash -c 'for i in $$(cat /proc/driver/nvidia/gpus/*/information | grep Minor | cut -d \  -f 4); do /usr/bin/mknod -Z -m 666 /dev/nvidia$${i} c $$(grep nvidia$ /proc/devices | cut -d \  -f 1) $${i}; done'" for RUN (char 167: invalid substitution type), ignoring.
Apr 23 08:30:03 systemd-udevd[485]: /usr/lib/udev/rules.d/60-nvidia.rules:4 Invalid value "/usr/bin/bash -c '/usr/bin/mknod -Z -m 666 /dev/nvidia-modeset c $$(grep nvidia$ /proc/devices | cut -d \  -f 1) 254'" for RUN (char 80: invalid substitution type), ignoring.