Use designated initializers to document positions in the arrays rather
than requiring counting. Use nitems() rather than rolling it by hand to
count elements.
Also, passify a Clang 12 warning about suspcious string concatenation
within an array initializer by adding parentheses.
Reviewed by: emaste
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26592