telnet: Remove usage of ALIGN

gcc doesn't like ALIGN() being applied to an array type. Just use
__aligned instead.

Reported by: Jenkins
Reviewed by: brooks
Fixes: 80203a27e964 ("Add sys/_align.h replacing machine/_align.h")
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D54290

(cherry picked from commit 3a4275a5f1f5dccd6918c4eff3b84488e322ad5d)