obs-qsv11: Fix HDR not working with AV1

Neither the mfxExtMasteringDisplayColourVolumme and
mfxExtContentLightLevelInfo structures appear to be supported when using
AV1, so if using AV1, do not include these structures.

It's unknown as to why AV1 fails to initialize when using either of
these extended structures as part of its configuration parameters.
Either they're completely unsupported or there's a member variable that
causes initialization to fail.

plugins/obs-qsv11/QSV_Encoder_Internal.cpp

@@ -370,7 +370,7 @@ mfxStatus QSV_Encoder_Internal::InitParams(qsv_param_t *pParams,
 	extendedBuffers.push_back((mfxExtBuffer *)&m_ExtChromaLocInfo);
 #endif
 
-	if (pParams->MaxContentLightLevel > 0) {
+	if (codec != QSV_CODEC_AV1 && pParams->MaxContentLightLevel > 0) {
 		memset(&m_ExtMasteringDisplayColourVolume, 0,
 		       sizeof(m_ExtMasteringDisplayColourVolume));
 		m_ExtMasteringDisplayColourVolume.Header.BufferId =