Add SET_MAX_BANDWIDTH to multistream encoder ctl list

Signed-off-by: Gregory Maxwell <greg@xiph.org>
diff --git a/src/opus_multistream_encoder.c b/src/opus_multistream_encoder.c
index 2877284..4cddbff 100644
--- a/src/opus_multistream_encoder.c
+++ b/src/opus_multistream_encoder.c
@@ -969,6 +969,7 @@
    case OPUS_SET_COMPLEXITY_REQUEST:
    case OPUS_SET_VBR_REQUEST:
    case OPUS_SET_VBR_CONSTRAINT_REQUEST:
+   case OPUS_SET_MAX_BANDWIDTH_REQUEST:
    case OPUS_SET_BANDWIDTH_REQUEST:
    case OPUS_SET_SIGNAL_REQUEST:
    case OPUS_SET_APPLICATION_REQUEST: