bsdinstall: Stop loading cryptodev for ZFS installations

[markj]

Summary

• zfs doesn't actually depend on cryptodev, and most arm64 kernel configs include std.dev, which includes "device crypto" anyway.
• This config works around a problem with kldxref, not with the loader, and this is believed to be fixed.
• Loading cryptodev creates /dev/crypto, which gives unprivileged users access to the kernel's opencrypto framework. Very few applications need it, so we're needlessly increasing the kernel's surface area.

Thus, stop auto-loading cryptodev.

[des]

You might want to clarify the first bullet point in the commit message: the second part of the sentence seems like a non sequitur or a typo if the reader does not realize that zfs depends on crypto, which is different from cryptodev.