Force AV_CODEC_CAP_HARDWARE set for OMX decoders

There are at least 2 out-of-tree OMX decoder implementations
that both lack AV_CODEC_CAP_HARDWARE, so they trick us into
thinking that neither of them is hardware accelerated.

Fixes false decoder warnings when linked against the patched
FFmpeg builds shipping on VisionFive 2 and LicheePi 4A SBCs.

app/streaming/video/ffmpeg.h

@@ -45,8 +45,12 @@ private:
 
     bool createFrontendRenderer(PDECODER_PARAMETERS params, bool useAlternateFrontend);
 
+    static
     bool isDecoderIgnored(const AVCodec* decoder);
 
+    static
+    int getAVCodecCapabilities(const AVCodec *codec);
+
     bool tryInitializeHwAccelDecoder(PDECODER_PARAMETERS params,
                                      int pass,
                                      QSet<const AVCodec*>& terminallyFailedHardwareDecoders);