qt/spu: remove max dma write size setting

This wasn't really used for anything tbh

rpcs3/Emu/Cell/SPUThread.cpp

@@ -673,7 +673,6 @@ void SPUThread::process_mfc_cmd()
 	LOG_TRACE(SPU, "DMAC: cmd=%s, lsa=0x%x, ea=0x%llx, tag=0x%x, size=0x%x", ch_mfc_cmd.cmd, ch_mfc_cmd.lsa, ch_mfc_cmd.eal, ch_mfc_cmd.tag, ch_mfc_cmd.size);
 
 	const auto mfc = fxm::check_unlocked<mfc_thread>();
-	const u32 max_imm_dma_size = g_cfg.core.max_spu_immediate_write_size;
 
 	// Check queue size
 	auto check_queue_size = [&]()

rpcs3/Emu/Cell/SPUThread.h

@@ -417,6 +417,11 @@ enum FPSCR_EX
 	FPSCR_DDENORM = 1 << 8, //Denormal
 };
 
+enum
+{
+	max_imm_dma_size = 0x4000, // Custom constant, represents the max number of bytes our mfc can transfer immediately, else enqueueing the command
+};
+
 //Is 128 bits, but bits 0-19, 24-28, 32-49, 56-60, 64-81, 88-92, 96-115, 120-124 are unused
 class SPU_FPSCR
 {

rpcs3/Emu/System.h

@@ -299,7 +299,6 @@ struct cfg_root : cfg::node
 		cfg::_enum<spu_decoder_type> spu_decoder{this, "SPU Decoder", spu_decoder_type::asmjit};
 		cfg::_bool lower_spu_priority{this, "Lower SPU thread priority"};
 		cfg::_bool spu_debug{this, "SPU Debug"};
-		cfg::_int<0, 16384> max_spu_immediate_write_size{this, "Maximum immediate DMA write size", 16384}; // Maximum size that an SPU thread can write directly without posting to MFC
 		cfg::_int<0, 6> preferred_spu_threads{this, "Preferred SPU Threads", 0}; //Numnber of hardware threads dedicated to heavy simultaneous spu tasks
 		cfg::_int<0, 16> spu_delay_penalty{this, "SPU delay penalty", 3}; //Number of milliseconds to block a thread if a virtual 'core' isn't free
 		cfg::_bool spu_loop_detection{this, "SPU loop detection", true}; //Try to detect wait loops and trigger thread yield