commit 0f55db36 upstream.

Otherwise the driver may try and send audio which may confuse the
monitor.

v2: set pin to NULL if no audio
v3: avoid crash with analog encoders
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>