sound: Retire unused emu10k1-mkalsa.sh

[christos]

Summary

It is a legacy script which is no longer used. Its utility is also
unknown.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

[christos]

Committed: https://cgit.freebsd.org/src/commit/?id=71c46c8c901be2a6e0708c912f0d766d49e5b335

I don't know why Phabricator didn't close this automatically.

[emaste]

If it doesn't close automatically you can add the commit via Edit Related Objects -> Edit Commits