muxer: Add 'dby1' brand when adding any Dolby Audio stream.
muxer: Add 'dby1' brand when adding any Dolby Audio stream.

l-smash/l-smash,mstorsjo/l-smash,canbal/l-smash,silverfilain/L-SMASH,silverfilain/L-SMASH,l-smash/l-smash,dwbuiten/l-smash,silverfilain/L-SMASH,maki-rxrz/L-SMASH,canbal/l-smash,dwbuiten/l-smash,mstorsjo/l-smash,maki-rxrz/L-SMASH,l-smash/l-smash