Added config option for AVX2 dataset init

-1 = Auto detect
0 = Always disabled
1 = Enabled if AVX2 is supported

src/crypto/rx/Rx.cpp

@@ -96,6 +96,7 @@ bool xmrig::Rx::init(const T &seed, const RxConfig &config, const CpuConfig &cpu
 
     randomx_set_scratchpad_prefetch_mode(config.scratchpadPrefetchMode());
     randomx_set_huge_pages_jit(cpu.isHugePagesJit());
+    randomx_set_optimized_dataset_init(config.initDatasetAVX2());
 
     if (!msrInitialized) {
         msrEnabled      = msrInit(config, cpu.threads().get(seed.algorithm()).data());