contrib: opus: don't build extra programs and doc
contrib: opus: don't build extra programs and doc

(cherry picked from commit bdd6d80e23f3358c887215fb0497dff79b799e09)

jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2