Remove the fuse.ko -> fusefs.ko symlink

On FreeBSD 13.0, the fuse driver will always be known as fusefs. The
backwards compatibility symlink will still be used for stable/12 and
stable/11, though.

Reported by: jhibbits
Reviewed by: rgrimes, imp, cem
MFC after: Never
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21181