bsdinstall: Stop loading cryptodev for ZFS installations

• zfs depends on the crypto module, not cryptodev, and most arm64 kernel configs include std.dev, which includes "device crypto" anyway.
• This config works around a problem with kldxref lacking cross-target support, but that has since been 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.

Reviewed by: kevans, allanjude, des
Differential Revision: https://reviews.freebsd.org/D45127