Remove bcopy(), bzero(), bcmp()

bcopy() has a confusing argument order and is actually a move, not a
copy; they're all deprecated since POSIX.1-2001 and removed in -2008,
and we shim them out to mem*() on Linux anyway

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12996

module/os/freebsd/spl/spl_vfs.c

@@ -85,7 +85,7 @@ vfs_setmntopt(vfs_t *vfsp, const char *name, const char *arg,
 	} else {
 		opt->len = strlen(arg) + 1;
 		opt->value = malloc(opt->len, M_MOUNT, M_WAITOK);
-		bcopy(arg, opt->value, opt->len);
+		memcpy(opt->value, arg, opt->len);
 	}
 
 	MNT_ILOCK(vfsp);