Add ibt=off kernel parameter

This is required when using the proprietary NVIDIA driver with 12th gen
Intel processors until NVIDIA makes an update to support IBT.

NVIDIA/open-gpu-kernel-modules#256

The open NVIDIA driver has been fixed, but prefer to use the proprietary
version.  The open version is considered alpha quality according to a
note on the Arch Linux NVIDIA wiki.

Add nvidia kernel module parameters via modprobe.d configuration
instead.

boot/bootstrap.sh

@@ -44,7 +44,7 @@ ${PACMAN_INSTALL} efibootmgr
 efibootmgr | sed -nr 's/^Boot([[:digit:]]+).*Linux$/\1/p' | while read -r BOOT_NUM; do
 	efibootmgr -b "${BOOT_NUM}" -B
 done
-efibootmgr -c -d "${BLOCK_DEV}" -p 1 -L 'Arch Linux' -l /vmlinuz-linux -u 'cryptdevice=PARTLABEL=root:root root=/dev/mapper/root rw initrd=/initramfs-linux.img nvidia-drm.modeset=1 quiet'
+efibootmgr -c -d "${BLOCK_DEV}" -p 1 -L 'Arch Linux' -l /vmlinuz-linux -u 'cryptdevice=PARTLABEL=root:root root=/dev/mapper/root rw ibt=off initrd=/initramfs-linux.img quiet'
 
 # Configure hooks
 sed -i '/^HOOKS=/d' /etc/mkinitcpio.conf