Adapt to new kernel installation

[maximbaz]

All official kernels no longer install the actual kernel to /boot anymore, this is done by mkinitcpio.

https://lists.archlinux.org/pipermail/arch-announce/2019-November/000397.html

This changes the hooks to watch for vmlinuz files in /usr/lib/modules, just like mkinitcpio hook does.

Seems to work, but let me know if there are some issues with this approach.

Probably fixes #6 too

cc @shibumi if you are still using this 😉

[saber-nyan]

Thanks! Will test your patch at the next kernel update.