Pulling in `hid-generic` kernel module

Since linux@4fdcfcca the hid-generic is a module now. The module is needed for a LUKS unlock with a FIDO token during boot, but when the token is not plugged in, the module is not pulled into initramfs during rebuild. dracut works around this by unconditionally pulling the module into initramfs, so mkinitcpio may do the same.

This was discussed with @foxboron over IRC.