audio/libsndfile: set PORTREVISION for Fix CVE-2022-33065

[Masachika ISHIZUKA]

  Hi.

  audio/libsndfile was fixed for CVE-2022-33065 in 
a1f663e8d4a65bdb5366a7992ebe02476a9d18c7.
  Please set PORTREVISION in Makefile.
-- 
Masachika ISHIZUKA