disp/decklink: always set max_aud_chans to value of 'mach'

set always max_aud_chans to BMDDeckLinkMaximumAudioChannels

Setting it to BMDDeckLinkMaximumAnalogAudioOutputChannels ('aach') for
analog output was incorrect, because eg. BMD Studio 4K has mach=16 but
aach=4. This subsequently crashes on assert, because
IDeckLinkOutput::EnableAudioOutput accepts only 2, 8, 16, 32 or 64
channels.

Author: MartinPulec

src/video_display/decklink.cpp

@@ -1286,10 +1286,7 @@ set_audio_props(state_decklink         *s,
 
         int64_t max_aud_chans = 0;
         HRESULT result        = s->deckLinkAttributes->GetInt(
-            audio_output == DISPLAY_FLAG_AUDIO_EMBEDDED
-                ? BMDDeckLinkMaximumAudioChannels
-                : BMDDeckLinkMaximumAnalogAudioOutputChannels,
-            &max_aud_chans);
+                BMDDeckLinkMaximumAudioChannels, &max_aud_chans);
         if (result != S_OK) {
                 MSG(WARNING, "Cannot get maximum audio channels: %s\n",
                     bmd_hresult_to_string(result).c_str());