Don't use more aout channels than the stream actually has to avoid upmix.
Don't use more aout channels than the stream actually has to avoid upmix.

Fix #9342

vlc-mirror/vlc,shyamalschandra/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,krichter722/vlc,krichter722/vlc,vlc-mirror/vlc,xkfz007/vlc,shyamalschandra/vlc,xkfz007/vlc,xkfz007/vlc,krichter722/vlc,krichter722/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,krichter722/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc